I am pretty sure that Open street map can be used in commercial products as long as it is attributed.
https://www.openstreetmap.org/
http://wiki.openstreetmap.org/wiki/O...r_similar_work
Not an attorney but they are certainly worth a look.
I might be able to make unit location maps using the openstreet map as the base. I built the font for mapping units and I would certainly give you permission to use it. If you are interested maybe pm me. No promises, my code is years old and may not still work, but it might be a nice addition.