wait wait wait I just thought of something new which could be the solution.
Please, have a look to the image of my motherboard:

- 13-130-080-11.jpg (63.89 KiB) Viewed 993 times
I could rotate the GeminiII 90 degrees clockwise making it to point towards the PCI Express Slots. If I do this, then the white PCI Express slot that's closest to the socket 775 would be unavailable because a video card would not fit there. So, I could instead just use the rest of the PCI Express Slots for my 2 video cards. I could use the yellowish PCI Express slot that is closest to the socket, as well as the white PCI Express slot that is immediately on the left.
The only drawbacks that maybe could occur with solution would be:
D1) The video cards can't be installed this way (the 2 cards must be on 2 yellow slots or on 2 white slots)
D2) The video cards won't operate at full X16 speed both, but on X8 speed. (According to the manual, to attain full X16 speed, both cards must be on the white PCI Express slots)
D3) The CPU Cooler wont work this way or it could be less efficient.
This are my 3 concerns on this solution. My questions are:
Q1) which of them would actually happen? Is there any other drawback here that I haven't anticipated?
Q2) If D2 could happen, then would my system suffer a performance penalty having one or both of the video cards operating at X8 speed? My 2 video cards are the 8800 GTS G92. I have researched on Google comparing X8 VS X16, and some say X16 performs better, while others demonstrate that they are the same, I don't know.
Thanks.