This is correct, but not as disastrous as it sounds. Unix won't let you (even as root) unmount a file system that has something going on in it. The automated scripts may try to kill all fusers of the device, but if the thing using it is the swapper, it can't kill that, so there's no way it would unmount.

Even if Maemo has some funky hack that lets it (unlikely), if you setup the swap space as a partition (vs file-based swap), it could unmount the fs on the card all it wants. Swap partitions aren't "mounted", but are turned on or off at the kernel level. Swap partitions have no real "format", just a header indicating their size. All the swap allocation information is kept in real memory.

Now if you were to open the back cover and remove the card while it's swapping to it, then you're hosed... Don't do that.

Actually, it's quite possible, if you have access to a fabrication lab and the equipment needed to do so. There are some companies that make SD cards with built in wifi and micro controllers in them. They look like normal memory cards to the host, but when near wifi and powered on, they can auto-upload your images to flicr or facebook or the like.

But unless you're a micro-E student, or work in a business that has micro-fab facilities, you're out of luck. If you do, be prepared for some expensive component and fabrication costs. You'll need to make it SDRAM at least, and will need to tweek the slot driver to not go into a total sleep state to keep enough power going to it to not lose memory. (So it would be a slight battery drain too...)

With the speed of flash writing (with 12x cards available), the cost of real ram would be tough to validate. Especially since most devices wouldn't be able to use it, since most aren't as tweakable. If you do have access to such a service though, may as well make a die of them. I'm sure you could sell the extras to forum members after showing they're valid.