Here's a pic of my 2008 750.
The connector on the top right has power when revers is engaged. It has two bullet connectors.
The connector on the left(tucked in beside the fuel tank) is live all the time. I have seen many guys use this molded conector to attach a trickle charger, usually for KTM machines where the battery isn't accessable without removing plastic. You could install a switch and run off this one as well.
2008 Brute Force 750EFI, K&N Air Filter, Dynatek CDI, Maroon Primary, Maxxis Bighorns(origional), Moose Bumper