Yeah, that definitely struck me as the odd bit in the article -- being jealous of the "fame" that startup founders get sure seems like a pretty specialized breed of envy!
At least in my company's market, a 'sales engineer' role is definitely going to be commisioned, and it seems like it meets the "demonstrating, guiding, training, advising, etc." criteria.
Lots of oportunities to work with customers, lots of technical involvement, and a strong position to influence product direction. It's also good background if you think you might want to move into product management at some point (or if you eventually get interested in engineering management, for that matter).
But (again, probably depending on market), the travel demands can be pretty significant, and you have to thrive within the culture and pressures of a sales organization. Personally, I think I'd burn out on it pretty quickly.
I'm glad to see this perspective here. It's bizarre how much of a sense of entitlement we can get working at jobs whose high-level description is 'go build cool stuff', and where if you're any good and you don't like the one you're at, there are 10 more looking for you even in a down economy.