For a removable CF card install, take inspiration from this plexiglass lid and CF drive mod empeg from kildal.dk, from before 10/2004.

Now I wonder, could a slaved CF drive work as a huge music buffer for the player and/or storage for the FID database? In other words, use the CF drive as RAM instead of a memory upgrade. Sure, we know the player chokes trying to fill a huge buffer, but maybe there's more to be gained here.