As an iOS Developer, how can I avoid upgrading to Lion?
You really can't. Unless you skip to Mountain Lion. It's one of the blessings and curses of being an Apple Developer and that is that you must stay current, or you're out of the game for both iOS and Mac Development. 

To use the latest bells and whistles for the next OS releases, you are really going to be bound to Apple's software and hardware requirements for those tools, otherwise you will find yourself spending too much time hacking together your build tools, instead of making forward progress.