Why do Kona Jake and Specialized Tricross have triple cranks on the lower models, and doubles on higher end models? Would be great if there was a little more choice (option of double on the lower end models).

I'm guessing because the higher models are aimed at athletes who are in really good shape and race them,while the lower models are aimed at commuters who are regular folks that carry gear/groceries.

Just a couple of ideas. Since these are both semi-offroad bikes, a triple might be just thought of as "standard equipment". I also think if you consider the entire US market, bikes with triples probably outsell bikes doubles by a large amount. So in the end, low to mid range triples might be actually be cheaper for the manufacturers than doubles.

Finally, the bike consumer on the entry level end of things might see more speeds as better and so it could be that doubles on the lower end models just don't sell as well.

I agree it would be nice to have the choice and maybe an LBS wouldn't mind swapping it out for you.

Dynaryder is correct. The double is a standard cyclocross double. Not a standard road double and not a compact double. It's a cyclocross double. It's built for cyclocross racing. The Sport model was introduced as a jack fo all trades type of bike. You could race it, but doubt Specialized had that in mind when they built it.

You do have plenty of choices. All you have to do is tell the LBS that you want a triple or a double or whatever. They'll be more than happy to accomodate you. Might cost you a couple dollars, but it'd be worth it to get what you want.