We may see Crash Bandicoot yet this E3, although not in the way everyone wanted. A NeoGAF thread says that the character has been listed as part of a Skylanders expansion pack, which sounds as crazy as it is entirely possible.
Let's remember this is how we saw the return of Spyro, so it's not insane to think this is going to happen, but the source is a retailer store Qisahn in Singapore. Don't get me wrong obscure retailers have leaked stuff in the past, but Singapore of all places?!
It's also worth noting that the retailer says the Crash pack will be a "PS4 exclusive"
We'll see if it pans out. Honestly out of all the E3 rumors I've heard so far (despite the source) it does seem the most plausible!