1 solution to run a dualsim adapter in a Nokia N95 is the analogue
UNIVERSAL DUAL SIM ADAPTER from 2-phones-in-1.com
You can run the simcards in 3g/UMTS Mode if you want.
Switching the active SIM requires a phone restart.
This can be done easily with a little Symbian tool.
Hypercard II also works with N95 if you run it in GSM only mode.