Here's a VAC crank with a ridiculously long stroke (a length which incidentally could get us into 4L plus territory for this supposed new block). Not proof of anything, but does show the measures people have gone to in order to get more displacement from the S54.
http://www.vacmotorsports.com/catalo...troker-kit.htm
Granted they also sleeve, probably to keep the thing from grenading. Don't get me wrong - these guys are competent.