lol .VNs running on the onscripter(tsukihime!) engines are portable. KEY developed VNs like Clannad and Little Busters have fan deviced methods of porting too. A translation patch for the ios version of steins gate has been done as well. A word of caution though..a jailbreak is needed for these 'ports' and patches. Word wrapping is also missing from most of these 'ports' and the size of these VNs are huge..for example Little Busters is close to 8 gb in size. I don't know how many people here have experienced a full blown 50+ hours visual novel reading experience but if you are vaguely interested in this medium of storytelling you should definitely give it a try.
