See my post here:
http://talk.maemo.org/showthread.php?t=37094

I wanted a great software (Mercurial) which hasn't already been ported to Maemo 5/N900.
I just had to set up the Scratchbox, build the software there and dump the files on my N900 !

Granted, this is just a command-line utility but still.
It reveals that everything is made to help the developer and not to obstruct him.

I'd be curious to see how hard it would be to do that on iPhone OS or Android.