Hi,
I have a USB harddisk (USB-SATA to SATA Harddisk). Is it possible to install AIX on this either from fresh install or using mksysb facility, get it to boot from USB? Was thinking along the line like LInux where you can install and boot a working OS from USB with tools like unetbootin or liveUSB.
Booting from USB requires BIOS support. Try booting DSL first. If you can boot DSL, then it is more likely that the USB disk is alive enough to support AIX. This post seems a bit sanguine: IBM: AIX - Has anyone installed/booted from USB drive?
If all else fails, can you boot from CD and mount the USB?