Mac128 pointed out this thread to me. Thank you all for your support. How to keep Mini vMac development going is certainly a concern.
But MacGeek417 is permitted under the GPL license to distribute his builds. I have no complaint.
MacGeek417 started compiling his variations before the Mini vMac variations service was announced, and had every reason to believe he was helping the Mini vMac project. And on the whole, it still may be of help. The more people using the source code the better, in the long run. He has made several bug reports.
The variation service can be thought of as just a way to more strongly encourage people to donate, since it is so easy to get around it. (Otherwise, the donation rate for open source projects is about 1 in 10,000, which unfortunately isn't enough to make a significant difference for Mini vMac.)
Currently the focus is more on ensuring a solid 3.1.x stable version, but for the future I have some ideas for additional perks for people who have purchased an activation code, to make it more compelling. I'd welcome any further ideas for such perks.