ideal treatment format

There is no standard format for treatments. I've read hundreds and they never look the same.

The only thing I would suggest is that you break it down into three acts.

Just for the record, treatments are not a good way to demonstrate your dramatic writing skills and treatments do not sell. In that respect, they are almost obsolete.

Treatments are most often used early in the story development process.

Can't argue with what ce says... tho' if you're determined to pursue this, here are links to a couple of treatment examples...
Link removed by request of the other site's webmaster

Pro screenwriter Bill Martell has made many of his screenplays available on his site for educational purposes, if you look at his scripts page and scroll down to the bottom you'll see his treatment for THE GHOST.

http://www.scriptsecrets.net/corner/script.htm

-Derek

That Link removed by request of the other site's webmaster article is great. I read it a couple of years ago.

I personally use a treatment--or an outline, depending on the situation--to bang out the story idea before writing the script. Since no one else reads it, format doesn't matter, which is liberating.

If someone is asking you for a treatment, you can probably send a 2-4 page synopsis and call it a day.