Maybe so, but quad-band is the easiest way of making sure that you get both 850 and 1900 bands on the phone. Tri-band, unfortunately, MIGHT have either 850 or 900, but not both...and 900 isn't used here, as you said.
Personally, I like my Motorola V635, but it's hard to get except off Ebay. However, it does fit all of your specs and then some.