Ever seen this mechanic before?

No, but instead of shouting first (or in addition to it?), I recommend grabbing for numbered tokens like in galaxy trucker. This way, it's clear to everyone who has which token, without any debate about who said first, first.

Edit* It's definitely not the same, but quickly putting things in containers reminds me a little of "Going Going Gone":

http://www.shutupandsitdown.com/videos/v/review-going-going-gone/

Interesting idea, but I'm not sure how choosing a truck first would be such an advantage, especially if many of the trucks had the same number of dice? You re-roll all of them anyway to get your points/etc., right? I could be last, but still have the best roll of the truck that was left for me. Or am I missing something? If you roll a "trap" at the end, what do you use that for?

Maybe it would be better to score the current contents of the truck you choose, rather than re-roll everything before scoring? That would make more sense thematically as well. What do you do with the different die faces? Are you collecting sets for points (stuff you are trying to resell)?

And what determines which die you can place in a particular truck? Are there limits, based on what's already there? And if so, how can you catch mistakes, since everyone is playing simultaneously? That's one of the issues with simultaneous speed games--you need to be able to check for mistakes at the end. (Galaxy Trucker was mentioned, and in that game, you must remove any tiles that were wrongly placed).

Does each player have a unique color of dice?

Practical issue: What's to keep the dice in the trucks while they are being grabbed? I can see dice falling out, or changing sides in the truck, if it's 3-D. Would probably have to have individual compartments for each die to keep it in place once it has been loaded.

Sound interesting. Let us know when you Kickstart it.

John Wrot!
Gate Keeper Games
http://bit.ly/KickstarterAdviceColumnsonBGDF

I really like the grab and add mechanic. I'm not so sure about all the dice rolling though. Custom dice are expensive and the degree of complexity resulting from the rolling and wotnot maybe too much for a game that is centred upon grab and add chaos.

After reading through the thread I quickly typed this outline out as it occurred to me. It might give you a few ideas.

Components

The 6 trucks are rectangular boxes, 3 cm long, 2cm wide and 2cm tall. Each box has 2 dividers that split the internal area into 3 segments. Wrapped around the boxes are truck graphics and the internals are black – although a top down view of a truck could be on the internal bottom of the boxes.

The trucks are number 1 to 6 by a large number on their rear (tail) section.

The players have balls that are 1cm in diameter. These balls are different colors. Red, green and yellow represent different types of cargo. Blue represents the police, black is associated with screeching tires and white represents broken glass.

Each player has 2 red balls, 2 green balls, 2 yellow balls and 1 each of blue, black and white.

The game also features a number of cards. These cards have a graphic showing a truck outside a gin joint in a landscape orientation. Down the left side are pictures of alcohol bottles in red, green and yellow. Next to each picture is a value number between 1 and 3. Each value is represented once.

So a card could have green 1, red 2 and yellow 3. Another card could have red 1, yellow 2 and green 3. These values represent the price the gin join is prepared to pay for bottles of that type.

Six truck counters for each player, numbered 1 to 6 on one side and featuring an investor hat on the other side.

A 60 second sand timer is used to mark the duration of each round.

Theme

The players are moonshine smugglers transporting illegal alcohol to three speak easies.

Set up

3 speak easy cards are drawn from the deck and placed in a line to represent the town. The top card is gin joint 1 and 2 and 3 follow beneath it.

The six trucks are placed in the centre of the table.

Game Play

The players choose 2 of their truck counters and place them to one side. The number should be face down.

The timer us turned over and the players can start grabbing trucks in their own time. Having grabbed a truck a player MUST put one of their balls into one of its compartments. A maximum of 2 balls can be in each compartment. Having added a ball they must immediately return it to the centre of the table.

When the timer runs out the round ends.

The trucks are placed together in a row, with their fronts facing the same direction.

The first compartment, nearest the front of the truck represents the delivery the truck makes to the first speak easy.

The players turn over their tokens to reveal which trucks they invested in.

The first compartment of each truck is considered. This will be relatively quick to do because all the first compartments will line up. The players score the corresponding point value on the top speak easy card for each red, yellow or green ball in the first compartment of the truck.

Any black balls in the compartment represent the screeching tires of a get away. One black ball cancels out one blue ball.

If any compartment in the row features a blue ball that hasn’t been cancelled out by a black ball the shipment was detained by the police and no points are awarded.

If any compartment has a white ball, representing broken glass, then every colored cargo ball in the same compartment (left or right) in the row is discounted from the scoring.

The scores are calculated for the second and third speak easy cards.

The players take back their balls and another round begins.

The first player to score x points is the winner.

Other Thoughts

The truck and ball sizes are merely an example. They have to be double the ball depth so that the balls can’t be viewed when the trucks are in the centre of the table and big enough to contain two balls.

Balls can’t be stacked.

The trucks could be bigger, say 6cm x 4cm x 4cm and the balls 2cm in diameter.

The balls could be cubes or blank colored dice.

The stack of cubes belonging to each player could be hidden from the other players behind a screen or in plain sight. Hiding the cubes will result in a very different game play experience than having them visible.

As Jeff astutely pointed out the possibility of a container toppling in the frenzy is a big concern. If this happens to a truck it will mess things up for everyone in a round. A simple penalty might be enough to illicit careful handling.

If a player topples a truck they have to pay an insurance forfeit to every player invested in that truck. 1 coin for each item of cargo it was carrying that falls out.

Speak easy = gin joint - sorry for the confusion