I don't know if this is a good or not but I saw this sliding table for sale on Raleigh CL for $200: DELTA SLIDING TABLE for tablesaw or shaper. It looks to be in like new condition.
I came upon this site here some time ago and it looks to be a pretty unbiased, comprehensive review of sliding table attachments. He rated the delta as "Although the Delta isn't perfect, it is worth what it costs." On Amazon it's been as high as $489, but currently at $369. I think that $200 is a steal and I wish I could swing it...