This forum frowns on the sale of Minis running OS X, which is the reason you did not return any results.
If your friend is unwilling to do the work himself, I would suggest trying to find someone in his area willing to help him out for a beer.
There are a couple of reasons we do not like third party resellers. Primarily, a hackintosh system may arrive fully functional and the 10vs go through software updates with relative ease, a Mini OS X installation will not update without minor tweaking, resulting in a less functional, inoperative or out of date computer. This concern is especially salient because of the upcoming release of Snow Leopard.
Resellers also often ship x86 computers without copies of the OS X installation disc or the original software, which can create headaches for the new owner.
Perhaps most importantly, selling non-Apple hardware loaded with OS X is risky for the community as a whole. Loading OS X on the Mini is a violation of the End User License Agreement of the software. The widespread sale of cheap non-Apple machines running OS X may force Apple to act by ordering this forum to close or undermining our patches through software updates. It may seem like a paranoid attitude but Apple is legally required to defend their intellectual property and the low commercial profile of this community is the best way to ensure its continued existence.