Personally, I love to see PE on CO. But I'm not holding my breath. Nor am I convinced it's a revenue bonanza for those who offer it. If it is, you'll see SQ, CX and so on jumping into the fray early on. Both of those airlines compete with BA, VS or BR on a lot of routes, but they decide to stay put. [And even SQ has PE on the 345, they decide not to do it on the A380; and QF is only putting like 2 rows of seats on theirs.] The future international heavyweights like EK, QR, etc also are not introducing them.

Anyways, if I were to design CO's 757 PE, I'll make it like the "business class" seats in European shorthauls. Convertible seats from 3-3 to 2-2 with more width and a wide armrest. [Perhaps add one or two inch of legroom, in CO's case.] Depends on PE/Y sales, they can convert the rows in a few minutes between the two products.