I'm in the process of installing OpenBSD on a regular PC. It's PChips M787CL+ motherboard with VIA C3 Samual 2 CPU, which I run with passive heat sink, so no fan here. I use DC-DC converter as power supply so no fan here either. And when I replace (as I plan to) a harddrive with compact flash card (using IDE-CF adapter) it will be completely noiseless. Maybe it's not exactly what are you looking for but if the noise is the main problem... In addition you can use regular keyboard and monitor, regular PCI cards (for wireless, etc) and pre-populate flash card using cardreader, so no need for remote booting.
Andrey
