I cannot see how TMO would be better with an app. on android and especially iOS apps are mainly there as the mobile optimised webbrowsers do not allow proper use of the website, so an app is needed for the extra functionality. This is not needed on the N900 as the std browser has full desktop style functionality and even "heavy" sites such as facebook and engadget work happily on the N900.

have you tried some of the alternat themes selectable from the box at the bottom of every web page on TMO?

combine one of them with a desktop shortcut and you are almost there.

9therwise i'd start coding as it is a scratch only you have and i would very much doubt that any devs would pick it up.