Hi,

I've read information on ifixit that the nexus 6P has a second sim card slot...

Does it have a second IMEI and can I use a modified sim tray to take advantage of this and does it work with the current firmware on the Nexus?

Nobody has cracked it yet, and interest has waned a little of late. I think the belief was you just cloned the IMEI from slot 1. As long as you're not on the same network, it apparently won't cause problems.

But nobody has yet modified things to get the phone to display the presence of a second SIM.