what you are asking is on the OS level, and I don't think it is a good idea. For example do you want your files in your PC spill to the D: drive when your C: is full?
on the other hand, a technology does exist to create a large logical drive from a few smaller physical drives, we are talking about RAID 0... and no, i don't want to have a RAID array on my phone either...
It is not that hard to make the habit save everything on the memory card. however if the a1200's file manager allow you to set default directory (or remember the last openend dir) would be great
