I am planning doing the Strathpuffer Lite next year, I am yet to decide what I am riding, but I would guess it will be as light as possible, probably not very retro.
I do have a Santa Cruz Superlite (currently being ridden around in the US by my nephew, that I was planning to reclaim when I am over at Christmas), but I don't know if I want to put it through 12 hours plus of my abuse, even new it was not a bike suited to heavy use.
I reckon a high end mid nineties bike is mostly a match for the recent models, but when it comes to downhill proper good luck stretching that envelope!