Thanks for the ideas, Narf!

I haven't talked to Ikea about this at all, other than a frustrating attempt to find such parts on the website.
Glad to know you have a few racks, but I fear the expense of getting them up to Washington might be more than they are worth. I still consider the easiest solution is probably to buy another entire rack; after all, most of the content is the racks and clips so even if I throw away the legs that is not too bad!
This is my first attempt at asking a question on IkeaFans, and I have to say I am impressed that I got a response so quickly. Thanks for the great introduction!