OK - thanks for checking anyway, I really appreciate the effort. I got pretty much the same results you did on enquiries - people had heard of it, but didn't where to find it. I did find a couple of consolation prizes, tho - a game save file that had all the parts, including the infamous HD-H10 head (DexDrive to the rescue!), plus a GameShark code that unlocks that part.
Here's the site where I found the game file:

http://home.pacbell.net/jujuboy/

Here's the GameShark codes for MoA:

http://www.cmgsccc.com/psx/index.php?game=33

An here's an AC design I just came up with - based on the lightest, fastest legs in the game:

Name: Sparrow
Head: HD-HELM
Core: XXA-S0
Arms: AN-25
Legs: LF-205-SF
Generator: GBG-XR
FCS: RATOR
Boosters: B-T001
Back Weapon Left: WM-S40/2
Back Weapon Right: WC-01QL
Arm Weapon Left: LS-1000W
Arm Weapon Right: WG-HG770
Optional Parts:
SP-MAW
SP-M/AUTO
SP-SAP
SP-AXL
SP-S/SCR
SP-E/SCR
SP-EH
SP-E+
SP-DEtq
SP-ABS/Re

This AC is lethal against other light-weights, but don't take on heavy ACs in this thing or you're toast! It might also be good against the Ex Arena ACs that like to bash you to death with their laserblades (haven't tried it yet, tho). Anyway, you can still lead them a merry chase with this design...

M.K.