I think all the anecdotal evidence that Perl works just fine on Windows 7 is failing to really answer the question until someone takes the time to comment on the specific stack / toolchain the OP mentioned:

• Moose: Seems to have a clean tester's matrix for Win.
• DBD::mysql: This is problematic, as it requires that the target system install MySQL Server first. Many GNU/Linux dists come with MySQL preinstalled, but Windows doesn't. Consequently, the tester's matrix looks terrible for DBD::mysql, when it's really not as bad as it sounds. I haven't specifically tested on Win7, but have on Vista with no problem.
• DBD::SQLite: No problem on any version of Windows I've used, and it has a pretty clean tester's matrix too.
• DBIx::Class: I've installed it on Windows Vista.
• Catalyst: I don't think I've installed Catalyst on a Windows system, but I don't recall for sure.
• Dancer: Should be no problem. The tester's matrix is clean. I've never installed it on Windows.
• ...and such...: I've installed Mojolicious on just about everything, including Win7. If you have other specific concerns please mention them.
• Perl itself: I've installed Strawberry (32 and 64) on Win7, as well as ActiveState Perl. I usually use Strawberry on Win (out of habit), but I understand that ActiveState has gotten a lot better with respect to providing the tools necessary to use the standard cpan utilities. My original reason for shifting to Strawberry Perl several years back is probably mostly moot if this is the case.

If you don't get anyone with specific experience installing Catalyst and DBD::mysql on Win7, send me a reminder /msg, and I'll reboot one of my systems to Win7 and do some test installs for you. It's obviously easier for me if someone else has already worked with those modules on Win7, but if not, after I get your /msg I'll go ahead and put them through their paces after which I'll follow-up here.