Personally, I can think of a few ham radio applications where an N800 could work well, but realistically, I think you're better off with a small, cheap (<=$500) laptop -- even something like an Asus eee PC if you really want to minimize space. Most amateur radio software requires one or more of the following:

-- Significant keyboard input (logging software, digital text modes)
-- Decent audio input/output capabilties ("soundcard decoding" modes)
-- Serial port and/or digital I/O capabilities

The Nokia tablets don't do any of these things particularly well out of the box; you need to add, e.g., a Bluetooth keyboard, USB sound card, and USB serial adapters to add them. So while you can certainly make it work, why not just use a small laptop and immediately get it all? (Or at least all but a serial port?)

I have nothing but encouragement for the people who want to do this, though -- just trying to explain why I don't think that many people are actually doing it!

---Joel