Several companies make midarm machines...
Bailey Home Quilter- can be used either sit down or on a frame and they come in 13", 15" and 17"
WoW sells a stretched domestic machine
Voyager is a 17" machine and is VERY heavy we're talking 75+ pounds but it's solid.
Handiquilter sells the 16" machine
Nolting has a few midarms as well.
Janome, Babylock, Viking etc have them as well. Pretty much just about every company has them - minus Singer but I don't think highly of the new Singers so there is no love lost there imho.
It all depends on how much money you want to spend. If you are looking to get more quilting space I would bypass the 9" machine if it were me and get at least a 15" or 16" machine