Did you ever figure out a way to do this? I am looking for a similar solution.
We have been working on this for 'awhile' (gross understatement). It started as an idea to make an app on top of PostgreSQL as a more user friendly product. Then the whole concept took on a life of its own.
1st effort ~ 1.5 years was MySQL and AS1. Switched to PostgreSQL a little over 3 years ago and it's close to being pretty good.
At any rate, the entire project is now about 10x what I had originally envisioned. Lots of layers on the onion.
The reason I even found your original post is because I am beginning to scout around for folks that have a good handle on PG & Actionscript. btw : an account = a schema.
I'll be announcing all of this early December on the PG site -- or at least in planetpg
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