This came up a while ago, and some TMPers talked about doing one. Here was my idea:
The app loads on one device, and players hand it back and forth. There is a "set up" phase where the GM loads the map. It is a grid and you simply "code" each square for whether it blocks LOS or not, and maybe indicate height (defined as 3 or 4 levels).
Each player names his units so unit 1 is "Heth's Brigade" or "2nd Squad." Units move 1 (infantry, towed guns) or 2 (cav/recon/vehicles) squares while hidden.
Player A sets up and assigns his units to squares per the scenario. He taps "next", his info is stored, and PLayer B now sets up.
Player A moves each unit. Player B moves. Now the computer determines which units can see which units. LOS is unlimited unless stated otherwise during set up (you could limit ti to, say, 6 for fog or rain).
A screen shows which units are spotted to BOTH players, and these are put on the table. Units on the table are tracked on the app but otherwise follow the rules of your game.
Once all units are "spotted" you just turn the app off.
Any takers out there?