I just purchased a Grace Pinnacle frame and am using a Janome 1600p on it. It has 9 inch throat and it's fast. I also got the Sure Stitch regulator, and the laser. They are on the Grace website.
I'll likely upgrade to a larger machine. My frame will handle one up to 18" throat space, like the new Babylock Jewel. I want to see if I enjoy doing this before I go and spend all that money. I'm up in Canada, and haven't seen a Bailey machine. From what I've been told, go as large as you can afford to go and plan for upgrading if you have to start smaller.