Ideas for my next project?

[Godlykepower]

After my very successful Surly LHT build last year, i have ended up with an outstanding all-rounder, but it is mainly road based and used primarily for touring.

I'm looking for something else to build now that is somewhere between my Surly and an out and out racing bike.

To be clear, I have no interest whatsoever in getting back into racing, but I want something more sprightly and faster than the Surly, that will have 700c wheels and thinner tyres than what I have now.
It won't be used year round and certainly won't carry any sort of load, other than a saddlebag of some sort.

I fancy building something that is beautiful as well as functional and as I've never had a bike with them, using Campagnolo bits.

I expect the answer will be something like an Audax bike, but what is available as frame only? I think I'd almost prefer something second hand though, which might be retro but not necessarily vintage. Something tasty with 531 tubing perhaps?

Names currently rattling around my head are: Mercian, Raleigh, Holdsworth, Peugeot.

Point me to something nice please!

 

[glpinxit]

After doing it twice before I'd be scouring eBay for a frame. But my lessons learned are that buying a full bike is much (much, much) cheaper that a frame plus individual components (even when some bits turn out to need replacing or upgrading) and I'm a brand tart so I endorse going for Campagnolo and finding a frame manufacturer you like.
I wouldn't be cautious about a full on race frame. Your body will quickly adapt to it from riding it and you already have a looser geometry bike for comfort.

 

[Spokesmann]

A nice build centred around a good quality Carlton frame?