I found a mod that just keeps them opening randomly, even after the main quest. Not sure where at, but I think it was on the Planet Elder Scrolls site. You cant open gates on COMMAND, but they keep randomly opening...
YAY FOR MORE SIGIL STONES!!
Cadaver
--------------------
You're such an inspiration for the ways that I will never ever choose to be.... (Maynard James Keenan - Judith)