Advise on book shelf speakers less then $750

I am looking for advice to help me upgrade my existing Linaeum LFX speakers monitors.  I am looking for used speakers with a price around $750 or less.  That have open, detailed with very good imaging and that are small monitors.  The living/dining room I have the speakers in is approximately 13 feet wide by 34 feet deep with 8 foot ceiling.  I normally listen to music at a low volume of around 50 to 65 dBs measured at my couch 8 feet from the speakers.  I mainly listen to jazz, blues, and some rock.  The system consist of a Threshold400a amp, a Threshold SL-10 preamp, Macintosh 7082 am/fm tuner, and a first  generation Sota turntable.  Before you start and say that I need to upgrade my components, have no interest in upgrading them.  And secondly by budget number is fixed and can not go up.  Because of WAF the speakers need to be book shelf size.  What I really want are LS3/5a made by Harbeth but they all seem to be above my budget.  Any thoughts?