Might I suggest starting with a complete bike then replacing things as needed or desired. Find a single speed that's close to perfect and start with that as a base.

Buying a bike a-la-carte is expensive and only worth it if you are the type that knows EXACTLY what you want.

My random thoughts on your parts list:
King headsets are nice and colorful, but they finish off a bike. They shouldn't be the highlight.
Thomson is nice. I have Thomson seatpost and stem, but they are only available in black and anodized silver.
Brooks saddles are overrated. Plenty of normal saddles out there that look and feel better that do not require "hundreds of hours of saddle time" to break in.
You've got some nice small parts, why skimp on the cranks? Go for Omniums or something nice since this is a wish-bike.
The cog choice depends on the chainring size.
Phil Wood hubs are nice, but I'd pass on them.
Tektro brakes are budget. You can get some used mid or high end SRAM, Campy, or Shimano brakes used for a good price.


Buying best-of-breed parts may not be the best idea. Remember, synergy is important. Your parts list isn't awesome. I can't see this coming together and being a show piece. Maybe have a look at Globe (Specialized) Bikes. They have some nice stuff that will probably be cheaper and better coordinated than what you are proposing: http://www.globebikes.com/. Plus, assuming that you have cash now, you can ride today as opposed to gathering parts over days/weeks/months then assembly in order to ride.