Yup. You could put some SRAM or maybe SDRAM+controller on the IDE bus and use this for swap (I think this is what some of the TiVO expansion boards do) but really you just want more RAM.

On a Mk2a you should be able to solder two more EDO RAM chips ontop of the existing ones, with every pin common apart from pin 14. Pin 14 of both chips needs to be taken via white wire to pin 123 of the StrongARM. Bingo! Another 16MB of RAM (total 32).

I suspect that the main board is over-decoupled enough to support this.

Hugo