Originally Posted by
Jburrow
My main concerns were the benefits and drawbacks of steel over Ti, and Ti over steel (high grade steel in this case e.g. Columbus Spirit/Life, Reynolds 853/953).
Since you have neither very specific nor particular demands, there are no drawbacks or benefits to one of those materials over the other insofar as performance or durability goes. Assuming equivalent design and construction competency, either material will produce an excellent bicycle likely to exceed any of your expectations. And even though I might have numbered lower buy-in cost as a relative advantage for steel, you've already defined your price range and it's sufficient to consider machines in either category. More than differences in build quality, performance, or reliability, at $4 - $7k, you're shopping for component spec, style, and prestige.
As for weld cracks on Ti, I'd say put that out of your mind, because there is absolutely nothing that I've ever seen in my 35 years of paying attention to cycling, pointing to any more an endemic frame failure problem with Ti than steel. Trotting out Mosaic as an exemplar of weld quality is pretty meaningless, as they've only been around about 10 years; how many bikes have they made that are even 5 years old? In any case, that you can find, on any given day, an abundance of 20- and 30-something year old Ti Litespeed frames on eBay says more about Ti durability than whatever Mosaic's record may be. Heck, there are 3 ~20yr old Airborne Ti bikes on eBay right now, and I'm fairly sure Airborne was as cheap as Ti got back in those days.
Regarding your thoughts on steel, you've indeed got a list of credible producers, spanning a great stylistic and philosophical range (neverminding that Pegoretti is dead; we'll assume, for discussion purposes, that a Pegoretti is a Pegoretti even without Pegoretti). If that's an acceptable range for consideration-- though I doubt you'll get a Pegoretti with rack mounts for sub $7k; ditto Speedvagen-- there are literally dozens of such builders across the globe, so the world is your oyster in that regard. With the favorable exchange rates, maybe a South African Mercer, a Canadian DeKerf, or a Colombian Scarab are worth adding to your list.
Actually, my head just exploded from all the possibilities, so I'm leaving now.