These seem really cool, I would assume the best way to get range and accuracy out of a low velocity, smoothbore weapon like an airsoft gun would be to use some type of fin stabilized projectile. I have always thought this type of solution would be excellent for sniper type applications where the prohibitive price of the ammuntion could be offset by using less of it. Though it would probably not go as far as an equivilent airsoft bb with backspin, I would bet that the accuracy gain could be significant.
Again though, one of the things I love about airsoft is the cheap ammo; I cant imagine this to be every be cheap, and you better hope they dont go out of business and stop making the stuff...