Considering a Single Speed Build

I've built bikes up from a frame, built many wheelsets, etc. I'm looking for suggestions for specific components, or general configuration, that will help me achieve the build I'm looking for. As most, I'm hoping not to break the bank, but will pay extra for better quality, lighter components.

What I'm looking for is a stiff frame with aggressive geometry and a comfortable fit. My frame size is around 58cm, plus or minus. FWIW, I'm used to riding in a relatively low position. With that said, I want to be comfortable enough for longer rides (2+ hrs.) I don't want to be as low as a track racer.

I'd like to get the bike down to around 15 lbs. A friend built a SS from a very light road/multi-gear frame and got his down to 13.5 lbs. I'm taking his word for it, but I did lift the bike myself.. very light. I'd prefer a track frame.

So, here are some options/condiderations:

Frame - Most likely alloy, probably with CF fork. I'm not against a press-fit BB, if only to save weight, but don't even know if a track frame is readily available configured as such. Is this do-able, relative to my final weight goal, for ~$500.00?

Wheels - I will build my own, probably from a kit like like this: DIY FG-SS Wheel Kit. I already have wheels with these rims and I love them. I might request that the vendor allow an upgrade to CX Ray spokes.

Other Components: Taking suggestions

I think the 15 lb. goal is doable or at least approachable. I'd appreciate it if anyone would care to jump in with ideas. Thanks!