I haven't seen one (but then again I'm in the UK) but I don't think that there really is a target market for that spec refurbished. I think Apple are more likely to take the SSD out and use it with something else because the 21.5 is really designed for standard users and I think anyone that would consider buying and iMac with an SSD from Apple straight up would be putting it in a 27" iMac
You can get good SSDs separately (The OCZ Vertex3 is one of the best and isn't badly priced) and be left with the Apple HD too