LOL, this has been done before. I have in my hands a PSX->amiga adapter (with analogue support) that supports the cd32 mapping completelly. plus it offers a "mouse mode" , you plug it in the mouse port and analogue stick moves teh mouse (duh)
here is a snip from the documentation:
>> Controller Mode Selection.
>> There are four controller modes supported:
>> The 'Select' button on the playstation pad is used to override the
>> current controller mode.
>> A more detailed description for controller override is given later...
>> a) CD32 Mode (Default) 'Select'
>> b) Traditional Joystick Mode 'Select + L2'
>> c) Amiga Mouse Mode 'Select + R2'
>> d) Atari Mouse Mode 'Select + L2 + R2'
next version will have mirroring/mapping of UP direction to a button (so JUMP in games will not be the ultra-lame up direction) plus in the works is a serial->ps2 mouse adapter for older pc's
EDIT: I forgot to mention, I have contacted the person that makes them, to check upon availabillity and status of the newer design... I will let you know