Skunks,
Even though Mutt may have incorrectly guessed your nationality, don't overlook the rest of his post. He's exactly correct when he says that the confusion lies in the two very different definitions of "jumpseat".
Your goal of living in one area in Europe and commuting to another via jumpseat would probably require something of a Reciprocal Jumpseat Agreement between airlines (like we Yanks have here in the states). I could be wrong, but I don't believe that any jumpseat agreements exist among European airlines (and again, that's probably due to the different definition of "jumpseat" there). Are you a member of a pilot union? Is there any possibility of jumpseat negotiations in the future?
In the meantime, what about commuting on your own airline? Does your company fly between your domicile and your preferred residence? If not, does it fly anywhere close to it? Do you get reasonable travel benefits with your company?
Another thing to think about: commuting isn't always a good thing - - have you done it before? You're always away from home a few more days per month, simply to get to and from work (with the usual inherent delays). I'm not saying this to discourage you, just to make sure you know that there are pros and cons.
Good luck, wherever you live! Hope something works out for you.