If you're going just for tank-like durability, get a Model M, possibly a Space Saver if you can find one for a decent price. However, you mention that you'd like brown switches, and you type quickly and would like minimal resistance. Due to that, I think you should be looking at the more well-known (and higher quality) TKL boards. Leopold is what I have, seeing as it's a great TKL board for the price, but do remember that it has a proprietary spacebar, so that would limit your replacing it,say, if it started to shine. I found that Leopold keys are amazingly resistant to shining, but that might just be my board. Filco's definitely a great choice, probably what I'd recommend, although pretty expensive, relative to other Cherry brown boards. You might also wish to look into the higher-end Duckys, but I personally have no experience with them.
In general, though, mechanical keyboards tend to be much higher quality than rubber domes. You needn't worry too much over the durability of it, get one mostly for the feel.