Haven't easily found anything on this subject but I'd be grateful if someone could answer this one.
First off - I assume that any Linux Build used on the Raspi will be holding Linux swap on the SD card.
Now I've had a play with 'low power' 'solid state' 'no moving parts' Linux Cigarette Packet Servers in the past with the wonderful Linksys NSLU2 NAS - this was a 266Mhz Arm5 Compatible Core device with 32Mb (ouch) of RAM that had 2 USB ports which you could hang Memory Sticks and whatnot on - there was a big 'health warning' on them though that they would not run forever because the Linux Swap was on the SD Card/USB Stick and these devices were certified for quite a low number of device writes before failing - and of course Linux Swap gets good and hammered on low memory devices - and indeed that's what happened to mine.
So - is this issue likely to afflict the Raspi? I assume the more expensive the SD Card, the greater the number of guaranteed write cycles on the card, so maybe we can buy our way out of the issue (if it actually exists)