You can fit any cpu card to a 1A without any modifications to the motherboard. So should you decide to go for a cpu card in the future then you're all set. 
As a last resort you can get a 4MB SRAM card for the extra ram if ram is all you need and you can't find any cheap trapdoor expansions. Now a SRAM card over the 16bit PCMCIA bus will slow down the A1200 a bit but at least you have enough ram.
Ive seen 2-4MB SRAM cards compatible with the A1200 go for quite OK prices if you dig around a bit.
