I've never tried this with perl, but you can usually move a ruby installation if you always give it -I parameters with the module directories. All I needed is a wrapper which figures out which directory your ruby is and adds the necessary -I parameters to the command line. Also, I compiled all the modules statically in the ruby executable, which is ugly, but you may be able to avoid this too. There may of course be problems with particular modules that assume they aren't moved after they're installed and search for data files (not ruby code or shared libraries) in particular paths, but in practice this doesn't come up so often. As I've said, I haven't tried this with perl, but I imagine it's possible with some work too.

One more hint. It may help if you check out how the makefiles test perl before installing it, because these scripts have to do something similar. The commands are quite complicated, but they may still help.