Hmm......Interesting frame. First thing I thought when viewing it was that it's got the wrong bars because of the shifters on the toptube and the choice of bars, stem & brake levers...The frame to me looks like it is designed for upright riding. But....What do I know! The toptube is short so I guess it could work fine. Just seems weird to me.
I don't like the bend the cable needs for the front brake and I hate the cable routing for the shifters (which is just aesthetic... but still). Where is the dynamo? Is it at the chainstay bridge? Are those vertical dropouts? I wish their were a lot more pics of better quality...
My favorite aspects are the way the front derailleur is attached...(It is attached weird isn't it?) To have it semi-brazed on in that fashion is really neat but would be limiting in your choice of chainrings. I assume from the builders reputation that they know best and the gearing chosen covers all bases just fine. To do that speaks volumes IMO about the builders thoughtfulness and knowledge (or the original owners desire). The lugs are very pretty and I love the derailleurs, crankset and choice of brake calipers (especially with the braze on posts for the brakes)...
Would I spend $2500 on it? Damn right! I'm sure it will end up much more than that. You would be hard pressed to have a frame built to match it for that price...Let lone outfit it with such pretty stuff hanging all over it. Oh! And it's a Singer which is just about as nice (or as nice) as any French constructeur bike ever made.
Not the ideal bike made in that fashion in my mind but.....I can't afford it anyways so what can I say?.

As a fellow Peugeot PX? owner.....No offense to the previous posters but.....Uhm.....This bike is in a whole other league. I don't think I have ever seen or heard of a Peugeot that could even begin to compare other than similar materials and component specs. And then there is the addition of custom handmade racks suited specifically for this frame and other bits like innovative uses for braze ons (front derailleur) and exact frame geometries that are suited to very specific load weight and placement requirements. This bike if compared to autos built in the same fashion would be IMO the Singer=Bently custom ordered with 4 pages of requests (and an in house catered lunch, fit session and build consultation) compared to a PX-10=Ferrari from the dealership floor.

Sorry I didn't list French auto makers......I just can't think of any good comparisons.
It's all just my opinion though...Nice bike!