Update on my Mercian: I built a new wheelset with 28-hole Ukai rims (recently on 50% off sale at SomaFab), a rear 28-hole Sturmey Archer AW hub, and a front 28-hole Novatec cartridge bearing hub. Total weight with steel-shelled hub, fenders, bottle cage and pedals is 22.8 lbs. Took it for a 20-mile test run today, and everything felt good. I do wonder if the gearing is too low as I did a lot of coasting on any descent and only used the low gear once (at which point my rear wheel slipped in the dropouts), but my plan is to take it for a 70-mile ride this coming week and see how it all works out.