I think we must stop to ask for be beta testers, 10.5.2 will come out in few days and so Zephiroth rel.2 I think.
I think also that Zephiroth is able to contact everyone on this site or on Insanely Mac (by PM, mail, everything) if he needs someone for test. If he don't needs more testers maybe there's a reason.
For me I contributed in testing video drivers on 8800GT, but no beta testing and I am waitng patiently for the release using Zephiroth Rel.1 as my primary system.
So: Good work Zephiroth, take your time, keep us informed on progresses!