Brewed my 1800's India Pale Aged Ale a few weeks ago, you can read my long break-down of what I'm doing and hoping to find out on my blog here: bear-flavored.com/2013/01/brew-day-and-recipe-1800s-ipa-india.html
Basically, I am planning to age the majority of the batch in secondary with Brett C, and bottle a small portion of it fresh. Then I'll save a few bottles of the fresh portion to drink in a year and a half or so after the Brett portion is bottled. I suspect the long aging process is crucial to determine what the beer actually tasted like back then, probably more so than pils malt vs Maris Otter vs. pale ale malt.
I'm also wondering if the presence of Brett is what made historic IPA taste good at all. I mean, no one ages IPA at all anymore, and for a reason: it tastes terrible aged. Even IPA that's only a few months old can be pretty bad. So the aging process of the IPA seems like a contradiction to me, but I think Brett's ability to rearrange hop compounds could play a key role. Hopefully tasting the Brett portion next to the "plain" portion will be enlightening.