Last I heard TXI was down to one FA-50, one FA-10, and the FA-200 was parked but still there.
Business Jet Center on Lemmon Ave (east side of DAL) seems to keep a bunch of big iron on the ramp.
I have not heard great things about Regal (they have a new DO so things might be getting better), and the only operator at ADS with anything big is Million Air.
I hope this helps.