Well I too would love to see this venture work, but I can't see it happening - and I can at least say that I have met the CEO in charge.
I like the principle, simply because I'm fed up with flying around in sardine tins, and don't mind the idea of paying a little bit more for some leg room. And let's face it, CO via EWR is neither comfortable nor convenient if you are comparing strictly with scheduled ops from BHX.
Using a tristar just seems daft, simply on the basis that old aircraft + cheap fares might work, but an attempt at a premium product on such an old beast? Less seats obviously also means more fuel burn on top of the factors already mentioned.
Globespan's daily GLA to SFB is ambitious, but they have excellent local branding, with a bit of help for marketing from the other end. There has to be more room in the market for innovative approaches to transatlantic flights, but BHX to Florida just isn't that place.
The good intentions might be there, combined with a certain amount of persistence to get this off the ground (is it now third time lucky?), but I just don't think the sums can work.