Pretty cool! Highway and any +buy can generally lead to very fast pile emptying.
However, I'd observe you were showboating a bit here, and didn't actually need to empty 7 piles, or even start on the cities. Steward + Highway + Grand Market is a powerhouse all by itself, with maybe 1 Farming Village to allow a second terminal, be it a Steward or a Haggler, depending on whether you prefer faster trashing or faster building. Either way, pretty fast, and no need for cities at all.
Steward/Steward and rush to Highway/GM:http://dominion.isotropic.org/gamelog/201210/16/game-20121016-042600-09613a62.htmlSlightly more complex, incorporating haggler, and going Steward/Silver to minimise number of terminals:http://dominion.isotropic.org/gamelog/201210/16/game-20121016-043305-7d1eb5d7.htmlOf course both of the above are solo games, with no competition for Highways or Grand Markets, but the key is certainly to rush those two cards as efficiently as possible, and if the piles of those empty, then there's probably a sneaky 3-pile ending available early anyway, such as taking the duchies or just a little VP and three-piling the Farming Villages.
Regardless, I wouldn't have opened Farming Village or Loan, as neither help get that critical early $5, and neither thin the deck quickly, both of which being the key to tempo here.