Infininight has posted at MythVillage that Andrew Meggs is requesting beta testers for Vengeance, the as yet unseen editing tool for Myth III. But if you're interested, hurry:

I'm looking for a few people, maybe 5-10, for a short beta testing cycle. These people should have a significant amount of Myth II mapmaking experience, their own copy of Photoshop, their own copy of Myth III, a decently beefy PC and graphics accelerator, and time to devote to beating on this thing in the next 72 hours (before Wednesday evening). If you meet all of these criteria and are seriously interested in helping out, please email me at insect@antennahead.com before around 11 pm PST Monday.

That only allows for 24 hours (give or take time zone differences) since he made the post, and about three of them have already passed.