Iphone App Customisation, Touchscreen game

I am considering developing a product for the Paintballing marketing (scenario games) and would like some input from software developers that could customise the IPhone Timebomb App. The objective is to build a dummy suitcase bomb and although the idea isn’t a new one (using mechanical timers), we want to take it a little further. We want to build suitcase bombs that contains a large format (15"?) touch screen version of the timebomb game so it can be used in the field as part of a scenario game, if the bomb isn’t disarmed before the time runs out then it triggers an explosion sound effect or something. We would need a basic demo version of the game in order to build a prototype first, then perhaps develop the visual aspect of the program later. If you have any questions, ideas or comments, please ask Thanks Martin