Great that this forum exists now. I hope it will thrive.
Let me start by saying I did ask this particular question on the official iPhone SDK forum as well.
I have seen a working example of a TiledMapServiceLayer subclass that overrides the GetTileUrl(int level, int row, int col) method to point to a TMS-compliant service. This is in the .NET API. I tried implementing
-(NSString *)tileURL:(NSInteger)level row:(NSInteger)row column:(NSInteger)column
and various variations but to no avail. Is there a workaround for this or does the ArcGIS iOS SDK just not support TMS?