I'm looking to build a 7 cards rig and I'm quite conflicted about what mainboard to get. There's scarce information about this as people usually try to limit their rigs to a maximum 6, so I've decided to make a short list of what I found on the interwebs during my research:

Working:

MSI Z77A-GD65 - link: https://bitcointalk.org/index.php?topic=186877.msg2206520#msg2206520
MSI Z77 MPOWER - link: https://bitcointalk.org/index.php?topic=285303.msg3049743#msg3049743
MSI Z87-G45 Gaming - link: https://bitcointalk.org/index.php?topic=449085.msg5469213#msg5469213
MSI Z87-G55 - link: https://bitcointalk.org/index.php?topic=449085.msg5700500#msg5700500
MSI Big Bang XPower (X58) - link: https://bitcointalk.org/index.php?topic=285303.msg3049743#msg3049743
ASRock Fatal1ty Z87 Killer - link: https://bitcointalk.org/index.php?topic=36061.msg4369450#msg4369450


Not Working:

MSI Z77A-G45 - link: https://bitcointalk.org/index.php?topic=97154.msg1069726#msg1069726


Unknown:

MSI Z77A-GD55 (probably not working, configuration similar to the Z77A-G45)
MSI Z87 Series (GD65, MPOWER) (probably working, configuration similar to the Z87-G45 Gaming / Z87-G55)
MSI Big Bang XPower II (X79)
ASRock X79 Extreme11
Gigabyte Z77X-UP7
Asus Z9PE-D8 WS


If you have any information on any of these boards or any other 7 PCIe boards, please let me know.

Hope this has been helpful for people looking for the same thing as I am.