Hy
I just found the 26th 3G magic Dual SIm Adaptor. (http://magicsim.com/en/dual_sim_show...G%20dual%20sim or http://magicsim.com/en/dual_sim_show...G%20dual%20sim)
This adapter should work with the n900, because it also uses the 007 shortcut menu, but you I think you will need another phone to activate this mode because there is no STK menu in the n900.
Anyone knows a place to get this adapter? I only woud like to buy 1 not 100 .
If anyone has any experiece with this adapter please tell.

P.s. I know there is another Thread about Dual Sim adapters, I just thought that a new thread for 3g dual sim adapters would be a good idea, if not just merge it :P