bOOls eYe's Safedisk Cleaner can unwrap past 2.51 - but the program has since stopped being updated for various reasons. So the latest version that can be publically unwrapped is 2.60.52 I think.
bOOl's site is
http://boolseye.cjb.net/ but I'm getting a 404 error when I visit, but you can download the tool from
http://gamefix.dxs.to/