Lots of good information in here. Gives me a lot to think about when toying around with the idea of dropping the bikes weight.
Here's my contribution. I was in a recumbent shop looking at 20" wheels, and I noticed some forks they had. Well, this one fork was all carbon fiber, including the steerer with v brakes posts. I don't know the weight of the fork, but it was light, and looked really cool, since the blades were aero. The mfg is velokraft (I think) but the price of the fork is $350!!! Dang, with that much money you could buy another frame. Anyway, just thought I would let ya'll know there may be a fork alternative out there.