Hey LaurieIan - after 1000 hours you are garunteed nothing. If you
get your CFI and have around 750 hours of Dual given and a fixed no of multi hours - they as they say 'garuntee' you an interview with their Comair Regional.
If they have given you any sort of 'garuntee' let them send you an official document or contract. Otherwise prepare to be royally screwed.
Also conversion of FAA to JAA is an expensive and tricky process. Additionally, Comair isnt the most economical school around in terms of aircraft costs and other related expenses. In a very real sense you will end up spending twice as much money. If all you want to do it time building try out some place like Naples Air Center. There are other smaller schools too that are far better and economical but you might have a problem in conversion because they might not be recognized by the CAA/JAA.
If you are looking to stay and fly within the US it is a different story. In that case attending a school like COMAIR 'might' and I repeat 'might' work to your advantage. This is keeping in mind that you have your VISA and work permit and all that bureaucratic mess sorted out.