Thanks to some help from Andy Dougherty, I now have a 64-bit Perl on my Solaris 9 desktop machine. Hooray! It was a simple matter of tweaking the solaris_2.sh hints file.
Now, to see what modules I can break!
Update: 5 minutes later... - Looks like Proc::ProcessTable blows up thanks to a readdir_r() call. Time for a bug report. :)