in reply to Compiling perl both 32 bit and 64 bit

You could pack both versions into a single archive/package using dedicated temporary paths (properly relocated to be installed under /usr/local/perl) for 32bit and 64bit versions. Then, the install script would select the appropriate path for the given architecture (i.e. uname) and install it under the correct destination directory (/usr/local/perl). Normally, you would have two separate RPMs, one for each architecture.