Yeah, it seems like Nexus 5 is here to commemorate Android 4.4 Kit Kat.
That means the current Cortex A15-spec chips are enough, with the QSD 800 sitting at the top.

(Tegra 4 sucks because its very developer unfriendly).

I'm guessing they'll be giving some away for free, and make a huge announcement on 31 October, coinciding with Halloween.

Anyways for now, I'm gonna start the Nexus 6 rumours
5.85 inch screen
Bezelless technology*
150 x 80 x 9 mm dimensions
1080p Resolution
2GHz Dual-Cortex A57 chip
1GHz Dual-Cortex A53 LITTLE.big computing
4GB RAM, 32GB NAND
13MP Camera, all the usual gadgetry
Android 5.0 Lemon Drops
....let's see how far this rumour goes