So, i've been thinking this through for quite a while. I beleave its completly possable.
Basicly, its a game similar to the "Prop Hunt" mod for TF2, but instead of Props, there are bricks. For those who haven't played Prop hunt it works like this:
Two teams are selected, each member of one team get randomly chosen with a prop (Or a brick for BL). They have around 30 seconds to one minute (Cant remember) to find somewhere inside the map to hide as the prop. Once they find a place where they think that the other team wont find them, they click to 'lock' they're prop/brick in place. In TF2 this makes the prop stand up, but in BL it will place a brick where the player is standing. Once locked you can look around without the prop/brick moving. After the time has ran out, the other team go out and find props/bricks that look out of place. They can then kill the hiding person easily with some sort of overpowered, close range weapon (In TF2, its the Pyro's Flame Thrower). Once dead you cannot respawn. When all the prop/bricks are dead, then the 'Hunting' team wins. Or if the new timer runs out (2-5 mins?), then the hiding team wins. Also, each time a hunter fires his/her weapon, he looses health. This stops people running around firing randomly. If all of the hunters die, then the hiding team also wins.
How I think the script would go for the hiding team:
When either a item or a custom playertype clicks, a raycast is fired downwards, and spawns the brick which is chosen randomly out of any non-special brick that is smaller than 4x4x5. Support for custom bricks could be included, but not needed. After the brick is placed, the player gets teleported somewhere far far away, but the camera stays spying the brick. This is so that you're player name isn't visable. If you click again, you're player is teleported to the brick, then the brick is deleted (Not killed!) and you can move around some more. You can set the bricks colour using your Paint Selector. This can be done before or after placing the brick.
The hunting team is fairly straight forward. A custom weapon may be needed to remove the players health when they shoot.
Also, some Preferences with RTB could be:
Brick size limit (X, Y and Z), for the limit of the size of which the brick is randomly chosen from.
Special Bricks, checkbox if Special Bricks can be chosen, these include ramps, rounds and fences, but it can't include bricks like Spawn Points, or Checkpoints.
Limit Paint, checkbox if the players are allowed to select the brick colour. If not it is selected to the following.
Paint Colour, if the above is checked, then the bricks are automaticly selected to this colour. Im not sure if you can have the colourset selection thing in Prefs, but if not just use some sort of colour code, then find the closest colour to that.
Health Lost on Shoot, the damage taken when the hunting team fires their weapon. Could be increased for more powerfull, single shot weapons (Eg Rocket Launcher).
I can do some models if needed. Just tell me what it looks like, and what it does and ill try my best. However I can't test anything untill I fix my laptop, or get a new one.
Oke, nao go vote :3