I'm still hoping for a full frame Rebel.
Speaking entirely personally (as a landscape and portrait photographer), even though I love my 5D2, cost will prevent me automatically updating to the 5D3, then 5D4 etc. I plan to use my 5D2 for another 3 years, then I can justify the cost of a new FF body then.
Whereas if Canon brought out a (significantly cheaper) FF Rebel, with a great sensor but more limited AF and less ergonomic finesse, then I might upgrade every time the body is updated. The real question is whether there are enough people like me, who would tolerate a great FF sensor in a compromised body, to keep the price low.