Very well put together Mark.
I'd second what Mark says in that if it's just flying for fun go microlight, it's really taken off here in Ireland and some of the microlight aircraft out perform the regular Cessna 150's etc and are a lot cheaper.
Newcastle airfield in Wicklow have a nice set up for microlights and you'll find lots of info on http://www.nmai.ie/
I would say that if your going the commercial route to do a class 1 medical rather than a class 2 to find out if it's possible. It's fairly pricey at around €600+ but well worth getting it early on if the plan is to go commercial.
The PPL(A) over here is quite pricey so it's well worth checking out schools in Florida that do the JAA PPL(A).
Even though prices are advertised at the €4000 mark, realistically it would all come to around €7500 when you take in flights, accommodation, car rental, visa fees etc.
Also this would be in something bigger like a PA-28 or C-172 (as opposed to a C-150 or similar over here) and generally include night rating, r/t licence, ground school, exams, flight test fees etc. Time wise, 3 weeks is very possible but 4 - 5 weeks is more realistic.
Engine Failure: A condition which occurs when all fuel tanks mysteriously become filled with air