If you are looking for a solid quilting machine that only does straight stitch, you can look at the Baily. People that have and use them love them dearly and tend to stick by them.
They're very affordable as well. You just can't piece on it since there are no feed dogs. They come in 13", 15" and 17"
http://www.baileyssewingcenter.com/test.html
You can also use it as a sit down or on a frame. So if you start off with a sit down way of doing it and want to go to a frame you can and vise versa. There have been several ladies who have altered a table or desk to fit it in there so you have a nice smooth top for your quilt to slide around on as well ;)