I want my next steel frame to have an EBB (I’ve been using one for 5 years with no issues and it looks so much better than the alternatives) and be belt drive compatible with Rohloff dropouts as an option. Definitely 2 sets of bottle cage mounts not worried about headtube size or seattube size. Fillet brazing would be nice too, I’ve an old Roberts frame hanging in the garage and despite having no paint and being a little rusty it still looks beautiful.
I think a custom colour option would be nice, if I’m going to pay a premium then I want something that looks different.
So from reading this thread I guess the only conclusion is that we all really want custom built steel. I think that’s what your competing against in terms of price, you have to be significantly cheaper than going custom