I don’t have an enclosure, but my XXL sits on a bench that is almost exactly 48"x48". Left to right if you include the electronics box it is “just under 48” wide, up front a have a small space of maybe 5" or so. Pictures can be seen here:
As for height I’m thinking that many of the designs I’ve seen are too low, to me it looks like it would be difficult to get to the back of the machine. Also, my bench is a little too high from floor to top of bench, which also makes it a bit difficult to reach the back of the machine, unless I roll it out (it’s on wheels). Side access would be a pretty nice feature as well. I’ve been thinking about an enclosure for awhile now, but my dust boot picks up most dust and the sound isn’t really too bad.
Dan