Items that would be nice,
SATA for my A1200T.
Warp3D drivers for my ATI 9200 so I can ditch my Voodoo 5, and stop using the 9200 as just a RAM card.
A fix for switching between AGA and RTG mode, some games through WHDLoad refuse to work.
That's about it 
Can't you just use a Pata to Sata adaptor? And what speed advantage would you get over a fast CF Card and IDE adaptor?