All three are reference models and 2GB which makes unlocking them to 6970s trivial. I can get about $200 to $230 on ebay because gamers like the 2GB reference models for the easy unlock and solid performance of 6970. I just plugged all three into a MB and had them hashing for 8 hours today to make sure they are solid.
Here is a link to recent completed ebay auctions on used HD 6950s - you may need to login to ebay to see it.
http://www.ebay.com/csc/i.html?LH_Complete=1&rt=nc&LH_ItemCondition=12&_nkw=HD%206950%202GB&_dmpt=PCC_Video_TV_Cards&_fln=1&_ssov=1&_trksid=p3286.c0.m1539
I would like to try and sell them for bitcoins directly to gain some reputation in the market. So before I dump them on ebay I am offering them for 70 BTC (or best reasonable offer). Price includes priority shipping in US. International shipping might be a few BTC more (I just need to check).
If you need any vga adapters, HDMI adapters, Display port adapters, PCIe power adapters, or cross fire connectors just let me know and I will throw them in (I have dozens of them). If I don't get any decent offers I will just sell them on ebay.
On edit: No response so sold em on ebay.