Most domestic machines will work for Fmq.
So what you need to think about is whether you want a machine that will also do decorative stitches, regular sewing and embroidery. To get something that does all of those things and has a wider throat you will be looking at spending upwards of $2000 for a new machine with a harp space of at least 10". These domestic machines have lots of bells and whistles, but they also take up a lot of space.
If you want a machine for Fmq only then you could go with a straight stitch only domestic machine that has a 9" harp space for between $600 and $1000.
I personally like to have the convenience of a needle down option for Fmq, but I fmq'd for many years on a vintage Brother machine that did not have that option. For me speed control isn't as much of a concern since my main Fmq machine has a very responsive and easy to control foot pedal-- some machines have foot pedals that are not so easy to control and those do require some form of speed control if you are planning on doing long quilting sessions.
Rob