I think I would try FMQ on your current sewing machine to see how you like the general process. Just make up some practice sandwiches and see how it goes. Recently, there have been a lot of sit down models introduced, from several companies. If possible, I would also go to a show and see different units in person.
here's a link to a search on this board. Lots of info:
http://www.quiltingboard.com/search....it+down&u=&s=0