This is a great summary - and could definitely be thrown up in the tutorials section (or even the FAQ!).
Thanks for the note about Paypal freezing - I didn't know that.
Just to chip in my own practices - I tend to ask for 50% on line art approval and then the balance when I turn over the finals. There are a couple of companies with whom I have a different agreement, but that's on a case by case basis. Also, I've found the games world to be a friendly and honest one so I think it's fair to assume a certain amount of good will and good behaviour with small presses. You should definitely make sure you have a clear idea of the parameters of the job when you start, but it's not always worth putting hard limits on numbers of edits right up front. Jobs are organic things and things come up that you don't expect. If the client starts asking for unreasonable changes then you can usually deal with it in a careful email rather than placing hard restrictions on the job in writing. A little flexibility on the part of the artist is usually rewarded with a little flexibility from the client when you need it further down the line. The best working relationships come about when artist and publisher get along well.