It can be done, in my search I did find a couple of shops (in the states) who claim to have done the conversion and priced up the cost for doing it on their website.
I may have the link on my PC at home, i'll take a look and if I can find them i'll post them once my net access is back up.
It'd probably work out too expensive and too much hassle though, so unless you're heart is set on having something pretty unique, bin the idea and get a cheap blowback instead....