Ya it's not a bad price for the spec, but it seems out of line with Surly's other complete bikes where the emphasis has been on smart component selection at an economical price point. Although I have a Rohloff on my Big Dummy you can't really argue that it is needed for a strong versatile cargo bike. A standard MTB drive train would be more than adequate and would keep costs low. After all anyone can buy a frame and throw together a pimped out ride - the purpose of the complete bikes is to let people throw a leg over a Surly at a savings.
I bet lots of BD are built up with an IGH. It's what I'd want on a utility bike: low maintenance, works in all weather, better chain life, simple. I think the rohloff is overkill, but maybe Surly is getting them at a good price? I don't know about the Mr Whirly cranks -- I thought there big advantage was being able to use a huge range of chainrings, and with an IGH, that's not such a big deal. I'd rather have a generator hub.