Re: Problem on using NVidia for 1AGP+1PCI cards to emulate 2 terminals.
Sorry for the delay in getting back to you on this issue. I've spent some time looking at this today. I setup an HP xw8000 workstation with put 1 GeForce4 MX 440 AGP and 2 GeForce4 MX 4000 PCI cards, for a total of 3 cards, running RHEL3-U5 (x86) with the 1.0-7676 nvidia driver.
I then took your XF86Config from your bug report in the post dated "08-05-05, 05:49 PM", and simply ran 'startx', and had 1 X screen successfully running off of each card, for a total of 3 fully functional X screens (running Gnome, if that matters).
You didn't comment what kind of motherboard you were using, however at this stage, I'd guess that is playing a large role in the problems you're experiencing, particularly with these errors:
NVRM: RmInitAdapter failed! (0x21:0xffffffff:686)
NVRM: rm_init_adapter(0) failed
I've attached a bug report from the system where I've set all of this up for you to review.
Please let me know if I've misunderstood any particulars of your setup.