Anybody have access to a PPC-based Mac?
http://darwine.opendarwin.org//


What about testing if SQLyog runs on it?
Refer to http://www.webyog.com/faq/5_71_en.html for inspiration!

This looks interesting.

Updated info:

DarWINE has been updated to 0.97 (and Wine itself is now 0.98, so probably a DarWINE 0.98 is comming soon too). Refer to: http://darwine.opendarwin.org/

Note that there is now support for both PPC- and x86- Mac hardware.

There MUST be someone out there who can test it with SQLyog?

I can't speak for Mac but I run it on Fedora Core 5 with wine and it runs great!