I was curious about the same thing myself, but given that we're unlikely to see it here in the conceivable future (can you think of a business model that would make it worthwhile with a population of 3 1/2 million?) I have to admit my enthusiasm's waned.
Although if there were an emulator and SDK I'm pretty sure I'd try them out of curiosity if nothing else.

It's an interesting thought: I thought smartphone development took some getting used to, but SPOT would be a really different model.