Threre light enough, they ride well too.
Something like this,For Sale in the forum would be a good start, middleburns like the guy is selling are also well worth buying, the'll last a lifetime.
Magura HS33's are still the brake in trials, for the rear anyway, wouldn't bother with one up front, most riders have a disk/v on the front these days.
As for the rest of the bike, cheap but quality stuff is easy enough to get.
Forks: Pashley etc, £25, non disk, very strong, steel, light, steel.
Headset: FSA Pig, get a new one, £15
Bar/Stem: I'd have riser bars, something like Easton EA50/70's, or Azonics.
Wheels: Whatever on the front, doesnt matter really, on the rear, Mavic EX721 (521) on a hope hub would be a good start, cost around £60 2nd hand.