I would guess that the chances of more studios with 2 beds a la OKW is slim to none for a couple of reasons.
1) As already mentioned, a room size issue.
2) It seems most new direct DVC purchasers are younger families, and prefer the bed/sofa combination. They don't think of their kids getting older or traveling with other adults.
And once the kids have left, a married couple staying in the studio often finds the couch and queen bed a better arrangement. I know my husband and I would. The couch gives the flexibility of an extra bed if you need it, but if you don't, actually creates living space rather than a bed no one sleeps in taking up all the floor space.