Best floorstanders under $1000 new or used

Looking for a pair of floorstanding speakers with a non-fatiguing tweeter (soft dome, fabric, or aluminum if not bright) to go in a 23X15 room with a 10' ceiling. Interested in Quad 21L, 22L, but they may be slightly too short. Interested in used or new and wanted to see if anyone has has any recommendations. Any thoughts are appreciated.
Maggie MG-12
That's a big room, and will need a big speaker and some power to fill it. You need to tell us the amp you plan on using, the type of music, and the source.

A bit above your budget there are Epos ES30s on audiogon. These are great speakers. Stretch to them if you can and I think you'll keep them forever.

The rega floorstanders have a reputation for a balanced non-bright sound, but I have never heard them personally.

I once demod some B&W DM603s, and they have a really BIG sound, that would fill a large room, but I'm concerned that the metal dome tweeter might be a little bright for your tastes. They were a lot of fun though, particularly on rock music.
Thanks for the ideas. Some of the integrated's that I'm looking at are a McIntosh MA6450 or MA6500, MF X150, or NAD 372 and the source is an entry level NAD 521BEE (to be upgraded eventually.)
What types of music do you listen to ? Do you want to be able to play air-guitar to AC/DC or bathe in the sound of a string quartet ? (I do both ... but finding speakers that do it all is tricky and/or expensive).
used castles
Martin Logan Aeriuses. I'd be sorely tempted if I weren't so happy with my Spica TC-60s. The Aeriuses are a little over your budget though, going for around $1,100/pr. used plus $200 shipping in the U.S. Spica TC-50s with a powered subwoofer make a great <$1,000 setup, and they're reasonably gentle in the treble. None of these are for head-banger music, and the Spicas might have a little trouble at very high volumes. Too, dynamic punch is not these speakers' forté. For vocal and acoustic material at modest levels, though, any of these will give you good detail, smooth midrange, unfatiguing treble, and spectacular imaging. The Martin Logans, in particular, offer terrific detail and subtlety, clearly differentiating the two low baritone voices at the opening of the Manhattan Transfer's "Blues for Pablo" better than any speaker I've heard, including the $3,000 Gallo Reference 3.
Prorec, Be careful to match the speakers and amplifiers. If you can audition one with the other, all the better. The synergy between the two could make or break you enjoyment. Not just any great amp with any great speaker will give you the magic. Nice room size. Happy Listening!
There is a pair of Triangle Celius for sale here now for $950. That could work for you.
Look for a used pair of Vienna Acoustics Mozarts -- easy to drive, warm and musical, beautiful cabinetry. Another possibility is Vandersteen 2Ce. The newer Signature version will cost you about or a little more than a grand, even used, but the regular 2Ce model comes up on Audiogon pretty often and is a fine-sounding speaker.