Nice!
Two-side texture support isn't in there yet, but it's on our to-do list. Technically there are some ways you could make this work, using some math nodes. But with a rolled up map tilted on an angle it would be very fiddly to setup. I think if I were in your situation I would make the map out of two sheets of polygons which are separated by a small amount (but not too small) and texture each one separately.
