Try a custom Columbus XCr frame built by Cicli Barco. It will probably be the lightest steel frame you can get. One big difference would be whether you get a steel fork or a carbon fork. Barco has both. They have a very sexy stainless steel fork with a carbon steerer tube for lightness (+ 250 euro). They just finished making a frame for me which will be shipped tomorrow. Gianluca Barco is quite fluent in English and very responsive by email. Here is their basic all stainless bike. There are many options. For a lugged frame the cost is a little higher, but they offer about 6 different fork crown styles as well as lots of lug options.

Here is a review of the frame by an English bike magazine. https://www.cyclist.co.uk/reviews/66...rco-xcr-review

TIG
Custom Road geometry
Barco stainless steel dropouts QR with interchangeable hanger
Interchangeable or braze on front derailleur
External derailleur cable routing with Wing support
Brake cable on top tube, external or internal (no extra price)
Seat clamp bolt integrated on seat stays
BSA bottom bracket
1 1/8” head tube
31,6mm or 27,2mm seat post
Stainless steel fork with curved blades
Engravings: BB, dropouts, fork crown, fork ends
Barco classic head badge
Italian badge on top tube (optional)
Customer name plate on top tube (optional)
Mirror or brushed finish included
One color paintjob or sandblasted decals included
Price: 2.620,00€ (no VAT included) (about $3,000)

My frame has every possible option and came in at 3,320 Euros including Chris King headset and shipping.

Brushed XCr stainless steel TIG welded

Stainless fork with carbon tube

Direct mount brakes

Stainless nameplate


Barco stainless fork with carbon tube