No JAA schools in Texas, indeed. I have heard a rumour that there's a school in Arizona trying to get JAA/CAA certified. You might want to check that out. I don't know the name of the school though.
I have no doubt the KNVVL knows about the conversion, but the authoritative source would be the IVW:
http://www.ivw.nl. However, I'm pretty sure the short version will be that you need something like 100 hours PIC before they'll let you convert your FAA PPL into a Dutch JAA PPL without doing all exams over again. And you'd definitely have to do air law and a skills test anyway. Just like the UK CAA requires. In other words, that won't be an option for you in the near future unless you do some serious hour building on your FAA PPL.
Having said that, I know that there are a few N-reg planes in the Netherlands for hire. One of the places is Air Service Limburg in Maastricht (
www.asl.nl) and there are a few members of my club (based in Rotterdam) who own N-reg planes privately and might want to hire them out to you.
Another option you might want to consider is to do your flying training at an FAA flight school in Texas, but not do any exams there (except the FAA mandated pre-solo exams which is a laugh anyway). Get all your lessons properly signed off though. Then come back to NL, do all the theory here plus the skills test. You can save a lot of money on flying costs that way but end up with a Dutch JAA PPL anyway. Do check with a Dutch school/examiner beforehand to see what sort of paperwork they need in order to accept the hours flown in the US as proper training hours.
One other thing to be aware of, if you want to do FAA training, is that there are two types of FAA schools, part 61 and part 141 or something like that. Only one of those types is SEVIS approved, meaning that they can issue you the paperwork for an M-1 visa. All the JAA schools in the US are SEVIS approved so this is not an issue if you do JAA training.