yes, it ought to be possible! and occasionally is, as you say.
I like Julian Rathbone's "Wellington's War", in which he manages to turn the dispatches, usually a fairly dull but worthy read, into a very readable novel accessible to almost anyone.
When I was at university I was trained in the theory that anything substantial that you had to say should be in the text. The footnotes shouldn't be used to carry on side arguments, alternative viewpoints etc. They should be mainly for citations. I think that's a good system, basically. If you've got something to say/argue that won't fir into the text of this chapter, perhaps it should be in another chapter? That's obviously the approach Rory has taken with his historiographic analysis.
This system was not really evolved to deal with detailed examination of primary sources, though, as there was less of that around at the time (when it was evolved, not when I was at uni!). All the same, I like the idea of further chapters rather than huge footnotes - Monty or otherwise. It's a good discipline for writers, I think, to work on the theory that everything has to go into the text. If you can't incorporate it, why are you including it anyway?
Increased enthusiasm for historiographic analysis is an interesting development in recent history. Not sure what it's about. Lack of trust in oneself is part of it, I think, part of the acute self-consciousness of the modern age. At the same time history has never been so excitingly written - the "Longitude" school of thought etc.