Let's try this a different way then

There's no reason smaller Maggies wouldn't work in your room, probably best along the long wall. 1.6s might be a good choice if that's your cup of tea.

IMHO, small point source monitors are best at disappairing and throwing a big soundstage. Consider Reference 3A, Proac, Totem, Focal

You can always add a sub later. Cheers,
Spencer

The new Magnepan MG.7s are stunning and would work well in that room. New they are only a little bit more than your budget.

First off, after owning MG12s and MG1.6s I can say I'm not a Maggie guy. While I can hear the virtues in them, they just don't convey the music to me in a way that lets me relax and feel it. Always find myself listening to the speakers/system in a technical way.
My last try was with the 1.6s and it didn't take long to realize they weren't my thang. I gave them to my grandson. While we were dismantling the Maggies, I had my Revel M20s playing the music I had just used to demo the 1.6s for the boys. Everyone agreed the Revels sounded better. Even my 84-year-old dad thought the Revels had more going on.
Under $1000 you need to look at used. I agree with Sbank above, except I'd through Revel and a few others in the mix.

There is a pair of Spendor S3/5 monitors listed here for $650. Put
those on a nice set of stands and I think you will like them. You
would even have some cash left over for a sub if you think you
need it! BTW, $650 is on the high side for those speakers.

I think the Adcom would sound a little ragged driving the Magnepans