There is some very fancy software that can remove noise easily, but you'd want to start with a good image to begin with. The latest gen of sensors can do 6400 with varying levels of noise, there are lots of reviews comparing the cameras with 100% crops to show the noise levels.

I don't think hdri is a fad at all though. I think its the future still, as we move toward display devices that can actually output high dynamics, right now we are just compressing hdri to fit into a ldr display.

And as for the k20d not doing true hdri, its my understanding that it can dynamically alter the iso level per pixel on the sensor... however i don't know enough about it to start arguing with you, methd... but if i'm correct then its pretty amazing, and if your correct then yes 'big deal'

Be very interested in any articles about the k20d that deal with this feature in more detail, so far all reviews i've seen have glossed over that.