I tried Leo4Allv3 on an SATA>USB drive. It boots all the way through to the blue screen, than switches to a dark gray screen with the spinning disk. Having already installed Zephyroth's 10.5.2, I have a pretty good idea of which options to choose during install. I don't know if the USB drive has anything to do with it, but will install to a Leo partition I had running before and report back.

Rick

Athlon 64x2 4000+
Biostar NF61S Micro AM2
Radeon HD2600XT PCIe
2GB PC6400
Pioneer DVR110D
SATA 250 GB x 2
Belkin 10/100 NIC
SIIG Firewire 800