Certainly. There was talk about 3 abreast first class on a Concorde even before she started flying - but it never happened. With the result that the whole Concorde was always 4 abreast, with no more elbowroom than on 6 abreast 737 or 10 abreast 747, and of course less headroom.

New First could probably fit on a Concorde (or, for the matter, Embraer 190 or Bombardier Global 8000) 2 abreast. Or more than that at 1 abreast... like this E190:
http://www.airliners.net/photo/Dalia...eage/2015897/L
Note that E-jets are 11 cm wider and 8 cm higher than Concorde. Bombardiers are smaller, though.

We know that Concorde´s 2,04 M is not an impassable barrier. Valkyrie proved flight at 3,08 M, and shirtsleeve cabin.

But when North American offered a passenger Valkyrie, it had a small cabin.

Lockheed and Boeing promised bigger cabins, at 2,7...3,0 M - and then did not build.

Tu-144 is bigger than Concorde, and flew - with a shorter range.

With realistic 2011 technology, how much cheaper could a realistic Concorde replacement be (for the same payload, speed and external noise)?
For the same price (and speed and external noise), how much range could a realistic Concorde replacement reach?