Mustfly,
To pick your flying school on the basis you want a job with one particular airline is not in my opinion the best informed choice in the world, even a little short sighted.
As the others have said training in the US makes little difference to post training employment prospects.
However if you really are that keen on Flybe you should look to consider training at Aeros, Atlantic of Cabair as these all currently have recommendation schemes to flybe; how many of the studenst actually get the recommendation I do not know you will have to research yourself. But I have met and have known individuals to get recommended from two of these schools.
However if it really concerns you one way round this is to pick a UK school that has an associated school in the US and that way you can still claim to have completed the training at one FTO, for example Cabair have a US school in Florida doing JAA training for the CPL, therefore if you then complete the IR at Cabair Bourenmouth you will still have technically completed training at one FTO. Though note I am not recommending Cabair (far from it, would be my last choice of the schools based in Bournemouth).
However from past experience you will find JAA approved FTOs in the US do tend to charge extra for JAA training compared to the equivalent FAA training at the same site.