Shuttle's got one: the SS40G is a small form factor Athlon box using that heatpipe HSF, supporting DDR266 and with the other goodies that the SV24 had for Celeron/PIII/Cyrix: USB, Firewire, 5.1 sound, NIC -- and the usual complaints (onboard video, no AGP).
But unless you're doing gaming, a very nice box. Good looking, too.
Haven't seen it for sale yet, but I'd expect it to be <$300.