Upgrade to my system - Speakers maybe

That’s a big room. You might consider floorstanders instead of stand mounted speakers to maximize your space with low frequencies. I don’t recommend a particular brand. You’ll have to pick speakers with a free return policy and try them in your space. No brand recommendation here is worth anything. Everyone Here pushes what they own  or are selling. 

@tgrisham I definitely am thinking about smallish floorstanders.  Fair point about recommendations.  Demo's are tough now and I can return something if I don't like it.  

@mozartfan Kits?  That sounds like assembly is required.  Not my thing.  

Maybe something from the Totem line? In the past I’ve owned a pair of Dreamcatchers. These are small bookshelves,so not what you’re looking for,but they have smallish floorstanders that receive high marks online.  

It sounds like your room is pretty well setup.  3' from the back wall is ideal for a lot of speakers.  I would look at a few products:

Raidho - the X-1 and XT-1 are brilliant speakers.  They fit neatly in your budget and are brilliant sounding speakers. The soundstage is addictive and the Raidho tweeter delivers amazing detail.   A subwoofer is necessary but will work with your HRS.  The sound is neutral to a hair warm in my experience and might not work with your Rega integrated.  I would look at a more neutral/forward integrated with them.  Musical Fidelity would be a good option.    

Verdant Audio Nightshade 1 - This is a touch above your budget but would work well with your rega integrated.  I would take your Revel's on trade.  They are very easy to drive and are my soundstage kings.  The special thing about this speaker is that the cabinet is fiberglass with a nomex core.  The cabinet is more effective at damping than MDF and the result is more detail and a bigger soundstage.  

Scansonic has a few smallish standmounts that are interesting.  MB3.5B is an interesting speakers but with side firing woofers.  Might be a challenge in your room as it is relatively narrow.  The MB5B would be an excellent option.  Scansonic is Raidho's entry level line. The tweeter is similar to Raidho's but is not exactly the same but you can tell it has Raidho DNA.  Amazing soundstage and much better bass response.  Again, probably would need another integrated amp.  

Other options.  Might be worth looking at the Spendor D7s.  You will need a different amp to drive them but they are wonderful sounding speakers.  Small stature and super refined 

Check out the Focal Kanta and Sopras.  The stand mounts will fit in your budget and the small no 2 floorstanders could be had used.  They have a beryllium tweeter but and although a hair forward, not as metallic as the Revels  

Given your budget, you have to check out the B&W 805 D3.  Again, you may want a different integrated amp but it is a definitive speaker in this price range.  

Full disclosure, I am a Raidho, Scansonic, Musical Fidelity dealer and obviously I make Verdant speakers. I have no affiliation with the other brands.  PM me if you want to discuss pricing.  

Vienna Acoustics Beethoven Baby Grand fulfills all your requirements.