As an airsoft player, a replica that shoots in the 300fps range with a .20 bb is getting to be a heavy hitter if children are around. That will pack quite a whallop if it hits you, nevermind forcing people around to wear saftey glasses.

I don't want something that shoots that hard shooting at any of my tanks, maybe a paper target...

Swath, yes I think there is a market for what your offering, it clearly shows with creeping deaths success. I don't believe they have cornered the market in any way, go for it!!

Creeping Death - How are you going to fit a version 3 gearbox in a tank? Thats 5 or 6 inches long and close to 8 inches tall.... Then you need to account for some type of adjustable hopup...