fuzz2050

My commute has changed, and I'm eyeing a new bike to cope with the new conditions. It's about 18 miles, but perfectly flat; my fixed gear has been getting a lot more use on it lately. However after a 10 or 12 hour day I don't always feel like the extra hour and a half back home, so I'll take the bus. Of course, sometimes the bus rack is full and I curse my full sized bike.

I'd like to keep the fixed drivetrain, it works well on my commute. I haven't found any stock fixed folders, but I'm a reasonably talented mechanic and can do the conversion myself.

Things I would like
Sized to fit my 6"3 frame
Horizontal dropouts so I don't have to use an ENO hub
The ability to change out parts at will, I like to fiddle with my bikes, so the ability to easily swap handlebars would be great.

I'd gladly treat this as an excuse for a complicated project; I've considered buying a Raleigh 20 and having my way with it, but they never seem to come up for sale in my area.

Are there any suggestions for either new or vintage bikes that could serve as the basis for this project?