Not sure if you know of this site, but there are usually one or few sit down long arms for sale. People many times buy them and just use them a few times and sale them to get a stand up. The woman that runs this site has been in the longarm quilting world since the beginning.
http://www.longarmuniversity.com/MachinesForSale.html
You might want to test drive the Sweet Sixteen/Tiara, with a hopping foot for comparison.