I have a few pairs of the Elan riser plates from a couple seasons ago--the big 20 mmm ones they used to mount on the HyperCarve. Last season (2000-01) they put a smaller plate on the HyperCarve, because, I think, the big ones were scaring people away. This year they were back to big plates, although they modified them somewhat.
In any case, when I heard that they were discontinuing the big plates, I called Elan and they sent me a whole bunch of them. I still have a few left, and would be glad to get you a set--how does $25 sound? Big, thick, and rubber-based, they are NOT really race plates, especially for slalom. They are meant to be very damp and flexible, for deeply carved turns on skis with lots of sidecut (the HyperCarve). But they would work. PM me if you're interested!