There is a command in Win2K called 'Runas'.
Do a 'runas /?' for the specifics, but I've used it often to call the 'at' command under a different name.
Not a Perl solution, true, but I use it to run my Perl scripts.
Hope that helps.
Actually, I investigated going that route as well, but you can't programmatically (through redirects or echo 'n' pipe) send the account password to 'runas' anymore.