Update: Realizing that I also have a 1g ddr2 desktop RAM (works on this mobo) to spare. I am willing to give it for free if u buy the mobo!
I have at least 2 of these, in theory each could support 5 PCI-E vid cards (with risers, of course). An ideal mobo for your mining rig!
You can checkout its specifications following this link: http://www.google.com/products/catalog?q=ga-m57sli-s4&hl=en&cid=8415665895046448360&os=tech-specs
I'm selling them for 3.3 BTC, shipping & handling included
US continental only, tho.
If you are interested, contact me via email: DaNmarner [at] gmail [dot] com .
I'll conclude this post with a oversized pic of the mobo:http://www.coolingconfigurator.com/upload/pictures/GIGABYTE-GA-M57SLI-S4.jpg