Well, technically, if it had some magic band capabilities, but no FCC/equivalent certifications, and if they happened to overlap amateur radio bands, the possibility for legal ham operations is there. But still pretty pointless for most, and of course there are no such capabilities anyway.

This tells me you've never built a radio, not even the VHF and lower ones you make reference to. I have (specifically, a Part 15 VHF WFM transmitter), and as an electrical engineer and a licensed amateur radio operator, I like to think I know what I'm talking about.

There _is_ a technological issue, because cost, complexity, and physical size are all under tight constraints here.
Not an issue of regulations, simply of hardware. But either way, no. It's not hard. No harder than, e.g., releasing two versions of the N95. Note that there was about 6 months delay from the initial N95 release (useful throughout most of the world) to the 850/1900 release (useful mainly in North America). As anyone would expect, they try to hit the big market first, and then fill in the niche cases with specialty models.

So you can expect to wait a few months after the main N900 release (useful throughout most of the world, including urban areas in the US) to the 800/1900 version (useless outside N. & S. America, but significantly expanding rural coverage in the US, and.adding coverage in markets without a network in the AWS band, e.g. Canada and S. America.).

Will there be such a release? Of course I don't know, since they haven't announced anything about it, but it seems likely enough. However, it'll definitely be a while if it does happen.