ESR has already helped several free software projects convert from CVS to Git using his existing computer. The bigger the project, the longer it takes. (Each attempt to convert the Emacs repos takes 8 hours with his current computer.) He has studied the C code for doing the conversion, and determined that the best sort of computer for doing these conversions would be as fast as possible (doesn't matter how many cores; this is a single-thread process) and would have as much RAM as possible. Graphics card? Whatever, who cares. Keyboard, mouse? Not going to buy those, he already has those. Oh, and he would prefer it not sound like a leaf blower so he is looking for quiet power supply and a case with large quiet fans.
He says that several people spontaneously donated money to help him buy a better computer. So he opened up a discussion for how to best spend the money.
Several people urged him to only use ECC RAM, which means either an AMD chip or a Xeon. Someone just donated $1000 (!!!) so he has pretty much settled on the Xeon.
Once he has this, he will go around to free software projects and offer to do the conversion for them. His plan is to grab a copy of the CVS repo, run the conversion to make sure there are no surprises, then ask the project maintainers to stop modifying the CVS repo while he runs the final conversion.
This seems like a reasonable service for him to be offering. Instead of each project figuring out the conversion process, he will become an expert on CVS to Git conversions (with more experience than anyone else) and he will have the purpose-built computer to do the conversions as quickly as possible. So he really will be saving time and hassle for the various projects.
P.S. He converted the NetHack repos, and stirred up a hornets' nest. Read about it here: http://esr.ibiblio.org/?p=6389&cpage=1#comment-1207141