Is Insomniac big enough to work on Spider-Man and Ratchet & Clank at the same time?
Probably. The two studios have created games simultaneously in the past. If memory serves correct, they announced both Resistance 3 and Ratchet and Clank: All 4 One on the same day, and released both games in a span of 19 days.
Last year they released 5 games, Ratchet & Clank, Song of the Deep, and 3 Oculus Rift titles.
Since they opened the North Carolina studio in '08, they've seem to have been focusing on a larger AAA title, like Resistance and Sunset Overdrive, out of Burbank, and the R&C titles out of NC. According to their R&C PS4 post mortem, they've been doing some cross-country collaboration.
My Spider-Sense says you don't got to North Carolina to see Spider-Man. I think there's a herring in that red spider suit.
On the other hand, Spider-Man does look very ambitious, and visually stunning, so it may be an all hands on deck situation.
Regardless, a R&C announcement at some point in the not to distant future is pretty much inevitable. I hope we find out something soon, and I hope it's a completely new story.
But, in any case, whatever Insomniac puts out, I'm there Day 1.