Any question answered...

My wife is thinking about getting a Charge Mixer 11 (I think, possibly 8). It has a Shimano Alfine hub gears, from photos it looks like the cable doesn't enter the hub at the end of the axle as I've seen on Sturmey Archer hubs.

She wants to be able to use the bike on the turbo trainer, would this be a problem with the hub gears, assuming I can mount it properly?

The cable attachment is inside the chainstays, so yes, an Alfine equipped bike is fine on a turbo trainer.