Im up for trying that too, i have an old laptop, same situation and have a space gig memory stick...
I was not aware that the access speeds would be greater with USB than the HDD itself, but i always learn something new when i come here...
Would the same apply if i installed a cheap second drive as i have a spare bay and i have seen the ibm hdds on ebay for 10-20 second hand for a 1 gig one...
Just trying to put some life back in the old laptop, i use it for linux now... So i guess that makes the whole process void doesnt it... Linux uses swap right? Can the same be done...