I sure hope so. I'd like to be able to stockpile a common head and have different colored versions, like you hit Pause (or the L or R buttons) and swap to Bubble Lead, Leaf Shield, Air Shooter, and so on.
I was thinking about this after I logged off... The cannon should be about 24 to 32 LDUs in length. (1 LDU -- LDraw Unit = 1/64", 24 LDUs is the height of a Lego brick, minus the stud on top (4 LDUs).)
that actually brings an idea two versions of the buster one with a hollow inside excluding the handle of course (like the ray gun and one with the traditional stud to compliment using different elements for different effects =]
my friend ure a genius also the unit dimensions helps I think the interior of the buster, more or less looks like this...
( l ) a hollow circle with a single bar in the middle the depth covering the avarage minifigure hand completely without affecting the forearm area. the exterior is a rounded rectangular shape with a nozzel at the end and on the side is a little energy bar for detail effect.