http://www.cbx.com.ar/Eldorado/index.htmTony O'Connor of Eldorado in Australia restored my Mach 1 seat back about 10 years ago.
The seat I sent to Tony was filthy dirty, the springs exhibited surface rust everywhere, the upholstery was worn and torn and the foam padding was a couple days in the sun away from turning to powder.
The seat came back to me as if through a time portal that led directly to 1960's Italy. The frame was beautifully clean and painted, and everything about it the reupholstery job was perfect.
That being said, I don't recall what it cost. I do recall that shipping such a large and heavy box to Australia and back from North America cost about as much as the seat restoration. I also recall that back then the US dollar was worth about 2 AU dollars and so the cost of the refurbishment less the shipping was a bargain. I think the AUD and the USD are closer to being equal in value now.
So I guess what I am saying is if you are looking for 100-point restoration, or you are a perfectionist or otherwise plan to show the bike you might email Tony about his pricing, research shipping and check the currency conversion.
Another option might be to order the seat cover and "other stuff" you need to do the job yourself or for a local upholsterer to use from Tony as I think he sells the seat covers separately.
Jim Franzen