+1 for Riese & Müller, it I might have some bias since I sell the brand. Technically you can tour on anything, but some of their bikes are setup particularly well for that.
The R&M Delite and Charger have dual battery options which can certainly add to the utility of the bikes.
The Bulls LaCuba could also work well or a Trekking bike from Haibike. I think getting something with a Bosch motor could be helpful since their are service centers throughout the world. It could make things a lot easier in the unlikely case that you have an issue with your motor system.
What sort of terrain and distances are you looking to do?