I'll come right out and say it. GTX 780SLI is the only real option for BF4 currently. All else will result in nasty FPS dips according to the slides we've seen. It showed a 690 getting 50fps. You can bet that dips to the low 30's.
Vram is an issue, but so is GPU power and 780SLI fits the bill for Ultra @ 1080p with 4XAA. The real ticket will be AMD's new offerings which should improve the price/performance offerings on both sides for this performance segment right at the time of BF4 release. What takes $1,300 to get today, will cost maybe $900 before much longer. BF4 will be a $1,000 game for me.