I know this is a bit of an older thread, but our homebrew club did a 55 gallon batch of this style, and it is $#@ing phenomenal. The one I just drank is VERY young for this style (brewed 7/12/12, bottled 8/10/12), but after knocking out some of my 'to-brew' list, I'm going to experiment with this style quite a bit. Oddly, we used a commercial yeast from a local belgian-inspired brewer (Brewer's Art) that they use for, amongst others, their signature dubbel beer (Resurrection). Ours was closest to the 'ambre' color, as we had about 10% munich (asked our club prez for the recipe, and will post).
The hallertau gives it a nice moderately spicy character, but this beer is huge and complex on malt....while all the while having a subtle lingering bitterness that comes through in a bone dry finish. Again, this beer, though not HUGE in alcohol (~7.1%) will likely benefit from 6-12 months of cellaring.
I think one of the keys to this beer was the fermentation schedule Jamil recommended in his recipe. 66 (I think) until it slows, then raise it 1 degree per day until it reaches 72. It will be interesting to taste some of the other members' batches who didn't control temp. Resurrection yeast, while obviously not the same as french ale/BDG yeast, supposedly had very similar characteristics, providing some herbal notes at lower fermentation temperatures in lieu of esters, its a monster attenuator, and flocculated very well, even in 1.5 weeks.
In any event, if anyone has any references on this style, I would love to read more about it (I must take credit as it was my idea to brew this for our club). Very balanced, interesting, drinkable beer that really suits my tastes (and, according to Garrett Oliver, one of the best beers with food, next to his favorite, saison, of course). I'm lobbying to brew the recipe again and do a vertical tasting in a year.
It would be a great style to experiment with Brett/Pedio, or wood aging. The only commercial examples I've had have been Flying Dog's Garde Dog (which doesn't seem to be a great rep of the style, according to the Almighty BeerAdvocate), and Biere de Mars by New Belgium. I thought the latter was great, though some say it fits more in the 'wild ale' category.
Personally, I'm going to try to make a blonde version of the style, with a bit of a cleaner malt character (maybe some victory or other bready pale malts) that allow the herbal notes to jump out a little more.
Vive la biere-