My old housemate made what you call a "steamroller" a few months back. Have you ever seen those paintball peashooters? Its essentially a long metal tube that detatches to two short metal tubes for storage. We sat around the house (stoned off our tits) trying to work out how we could make this into a smoker aid. We even drew up blueprint and hit! haha. Ill try to explain how it worked.

essentially, the metal tube is open at one end for it to go in your face. The other end has a rubber stopper with 4 holes in it. In each hole we put a see through plastic tube that comes right back along the tube towards you and turns and goes back again to the far end. At the end of each tube there is a rubber stopper with a hole to work as a shotty hole (I dunno what the term is for that, but you know what i mean. It has the same purpose as the hole on a bong) and another hole to put a spliff in. So basically, its a 2 man job. One person lights the 4 joints and covers the 4 shotty holes. The other just tokes it and pulls all the smoke through the 4 spliffs, right down and back up the seethrough tubes and into the metal tubes. When the toker gives the signal that the things full, the other bloke lets go of all the shotty holes and the toker takes it all like a kick in the head!

Its quality.. gets you well mashed!