I agree about the unfortunate unavailability of the past works; I'm going to make it my project this week to compile the entries I have (not all, but the majority from the last year) and add them to the "Can I Suggest an Art Contest" thread, along with the names of the past winners.
EDIT:Just for folks' edification and entertainment, I've started compiling the previous entries for the monthly challenges here
(it made as much sense as anywhere, since to know what to suggest, it helps to see what has been done
). If you were an entrant for which I have no artwork, feel free to contact me, and I'll update the pages.