Ok, I feel dumb. I've put many hours into this and found nothing, yet.
When I was using Windows I had this little tool called WinSplit Revolution.
What it did was letting you divide your screen into how many and of how much size you choose "virtual monitors". You set one time of you want to divide your monitor, then everytime WinSplit is opened the monitor is automatically divided into Virtual Monitors.
I'm now using a 30' which i want almost always divided into 4 equal size "virtual monitors" (plus my mbp 13' those will be 5 1280x800 virtual monitors)
Now I've switched to Mac OS X and can't find anything that does just this efficiently.
I tried Divvy but I found no way to divide my screen into arbitrary "virtual monitors", I need a couple of clicks to select a 3x3 space on a 9x9 grid.
Before starting coding something like this can you tell me if you already know of some software that does window management like this?