I ended up getting this finally working with... drum roll.... different cables! I read online about how temperamental 10G Base-T connections are, even with the right cables and right ends. I tried several that should have work and finally found two that worked well. Thanks for the suggestion though. I am already on the latest firmware, but always a good first step.
I'm trying to figure out what I'm missing here. I've been banging my head on this one and would be glad to learn it's something simple... my problem is, when I connect from the 6224 using either of the ports on the 10G Base-T module, I can't get the link to come up (no link LED's on the module, or the NIC). Details: So, I am trying to do the most basic test possible. Just power up the machine and hold after the BIOS post (no OS, no drivers). What am I missing here? Anyone got any further tests to suggest? Thanks!-Jim   
6224 + 10G Base-T, can't get links to come up