SWBKCB, Jet2 are the most sensical one I think, and if they ever manage to get any 767's or A330's the might actually give it a go. Although they could do it with the 757's and there may even be a business case for it I just don't think they will.
Thomas Cook... x2/x3 weekly A330, with regards to low cost O&D I reckon it could have a chance. If they set up an agreement with an airline at JFK (Jetblue?) they could probably support about a x5 weekly A330 in the summer at least.
Emirates... Why wouldn't they give them the rights? If I'm not mistaken they may actually already have most of the required rights (UAE-EU/EU-USA/UAE-USA open skies agreements). The only opposition would probably be the US3, but if United canned us then how would they have a leg to stand on? Apart from blaming the ME3. With their plethora of connections at JFK I think Emirates is the best option we have... They did Dubai, why can't they do it again?
They're all long shots, but for now we have United, I'm happy with that, I'm confident they'll be here next year and I hope I get a chance to sample them... As I mentioned before I just hope the schedule next year is slightly more comprehensive, late May - early September seems decidedly half arsed
Regarding Air Iceland, that actually wasn't a joke hahaha, I know what I said on the ABZ thread but I know the Q400 is a much more capable aircraft than that, it still has a lot more of it's useful range to play with on ABZ-KEF. For us I think it could be our best bet at a KEF service, I can't see Easyjet doing it, nothing been hinted at by Jet2... Thomson? Winter only charters, maybe... I'll be keeping my fingers crossed that this new Icelandair initiative works out well for Newcastle, a 757 would have been too big but the Dash is a good size!