I do know of people who keep a separate perl install(s) in their home directory for testing. I think you can find the info in the INSTALL file. Here's my suggestion: When you configure, add the system-wide /usr/lib/perl5/site_perl to your lib path to include any PP modules you have installed. It will just ignore(overlook) any compiled modules due to differing build signatures. When you add modules, they'll go in your 'private' lib directories and the existing PP with rebuilt XS and new PP will live happily. I believe this will achieve what you want.

HTH

Update: Ah, an oversight! BrowserUk stated what you wanted to know, and above is the idea to minimize losses. Here's what I meant by build signature: Slackware 9.0 ships without threading, pretty vanilla. It puts it the compiled parts in a directory, i386-linux, that is a short description of the major build options. I rebuilt my perl, now my compiled modules go into i686-linux-thread-multi-64all-ld (yeah, I picked a lot of options ;) Maybe this describes what I was trying to say better.

mhoward - at - hattmoward.org