I have a feeling they will have a SIM card for the phone. Otherwise it wouldn't make for a great world phone
Verizon has SIM slots in some of their phones in order to be a world phone on GSM networks.
I think the same will apply here. Knowing HTC they will follow up with a phone that will be equivalent in a next HD3/HD4 release for 850/900 networks.
They are truly moving the whole phone market at the moment. They are the phone company to beat in regards to style and innovation.
I do like the Samsung Galaxy S as well. But I have become attached to the Sense UI and that is one of the main reasons I do not want to get the Nexus One for AT&T. I will pay a little more to get the one from Telstra is AT&T doesn't release any news of a better android phone by April 27th.
I am due for an upgrade or I will move to Sprint for the EV0 4G which I think I will get anyways.
I have the Tmobile HD2 and the lock ups pisses me off even with several of the other ROM's I have flashed.
Oh well can't have everything. I might return the phone. I have a few more days.