> Naturally, there are no guarantuees that Apple would or would not sue a small
> software developer

I know a case that has nothing to do with patents but with trademarks:

http://keyj.emphy.de/apple-lawsuit/

The programs in question went by the names of "KeyJnote" and "reTune". "KeyJ" is the developer's handle since year dot, hence the choice of the original name.
From this incident I conclude that Apple wouldn't refrain from suing small or even single developers over IP matters.