Have to add a few things....

It is fairly easy to order service with the cheapest phone available and receive up to $150 in rebates after the cost of the phone. Order the TriBand phone you want from a specialist phone retailer and swap the simm into the "good" phone. Keep the cheapo as a backup.

The new product releases from Moto and SE include the US market. High spec Triband phones are on the rise, but I still don't expect the service retailers to stock them.