Yep. Well, I've connected to the terminal block, and I have run wires up onto the dashboard, but not actually 12v onto the dashboard...
Actually I've wired (via an inline fuse) a 4 way cigarette lighter block into the switched live and I run my PDA/Phone/TomTom, BT GPS, BT Headset Charger and occasionally the Kids DVD player off it.
None of these devices is actually 12v, most are 5v and have voltage reduction stuff in the plug end of the cigarette lighter lead.
There's a very good write up on
www.icecavern.com on
how to get to the terminal block and what to connect to for switched live and earth.