I seriously looked into building an 8x68S on a ZG47 action, using a Lothar pre-chambered barrel, but then a Rem700 in 8mmRemMag came along and diverted my interest. Ideally, I'd build one on a commercial M98 action and I'd be looking at a minimum of 24" barrel. Dies, cases, factory ammunition is a pain to locate, so be 100% sure before spending the money to start building.
Cheers...
Con