I haven't seen Landrush. But what I was envisioning was something along these lines:
1. A large circular map that was basically as geographically neutral as possible. So no areas that are stronger or weaker than anywhere else (which, ironically, is exactly what the original Risk wasn't - re: Australia), although the center of the map would be characteristically different than the periphery.
2. Something in the form of a large honeycomb-like pattern. Or, a spider-web. Or a neural-network. There would be some "clusters" of territories that would give continent bonuses, and the intervening territories could give smaller bonuses.
3. The grid would be radially/rotationaly symmetric.
4. An onion-like structure could also work (theme Solar System?) where parts of concentric circles would form continents.
5. To reduce the amount of "neutral" territories, I think the number of territories would be optimized if it was a multiple of 24. e.g. 144 is divisible by 1, 2, 3, 4, 6, 8, 9, 12 and 24. 168 is divisible by 1, 2, 3, 4, 6, 7, 8, 12 and 24.
Anyways - I'm sure you guys get a lot of ideas, but if this sounds like fun to anyone, I'd be happy to develop it.