http://www.generations-quilt-pattern...e-reviews.html This has some reviews on it that may help.
I bought, 7 years ago, an Elna 7200 for £900/$1400 and although it has been, and still is a fabulous machine, I would never buy a modern one again. I prefer the stability, durability and dependability of the older machines. Although your wife's first quilt was made from Jeans/Denim I doubt that she will be making heaps more so what you need to do is to go for a good all-rounder machine for quilting.
All makes of machines up to the late 70's were manufactured to a very high standard, were made from metal with a minimum of plastic bits n pieces. This link has loads of opinions!
http://quilting.about.com/od/essenti...g_machines.htm
I did a quick search for you and found this company "Allbrands.com" and spotted what looks like a fantastic buy, this Refurbished commercial grade Singer
http://www.allbrands.com/categories/...rade-freearm-s for only $299!!!!!!!!!!! When you read the spec. it looks as tho' it would sew through anything especially with that extra powered motor.
Do let us know what you decide on.