Possible upgrade path

I'm in two minds about what to do. I'm currently using a 780 to drive two 1440p monitors(pb278q) and I'm looking to upgrade to a Surround setup for 7680*1440.

I'm just not sure what GPUs will be required. I figure I'll need two, but I'm not convinced the 4GB of the SLI 980's will be enough considering I'll be driving substantially more pixels than a 4k display. I'm open to the idea of getting a couple of titan X cards, although I wouldn't be buying them both at once. Probably buying one, get the new monitor and then finally add the second titan.

I feel like I should be waiting for the 980ti, but equally I don't want to wait around for ever. Put it this way - I don't thinking I would be a bad choice by any means to go down the Titan route; but I've never had a reference card before and I'm a bit concerned about the noise.

Any advice?

980 ti probably wont be a thing. If you can spare the expense of a titan I'd say go for it but wait until amd launches the 300 series to see if prices drop. Also there are going to be 8gb 980's so i'd probably get that.

Seems reasonable - I just wish AMD would hurry up. Feels like they've massively over-produced the 200 series cards and are just trying to move stock now.