@amiga4001,
I dont know how serious you are about getting this going but
I think your best bet would be to put the picasso2 in your A4000d with the ppc. That would be the best conf for a AmigaPPC linux box.
The A4000T would give you alot more room for your mediator+voodoo.
That setup would give you a nice 68k machine and a very fast/stable PPC linux setup.