What comes after Harbeth 30.1s?

A few weeks ago, I created a post where I was asking for advice to help a family friend create a home office system on a $6-7K budget. He ended up buying a VTL I-85 integrated amp which he really loves. After searching for speakers, he really liked my Harbeth M30.1s. He eventually bought my speakers but was going to pay in October. Unfortunately, he has had some unexpected expenses and won’t be able to pay me. So the speakers will be back in my possession next weekend.

The problem is that during this time, I started researching my next set of speakers. Of course, a safe bet was to stick with what I know and buy another pair of 30.1s whenever they pop up in the used market. Now that I will be getting them back, I’m still wrestling with the idea whether I should try something different. At this time, I’m only looking to buy used and not spend much more than what I can sell the 30.1s for. And to be honest, I will only be switching for the sake of trying a new flavor. I really like the 30.1s and something tells me that I might come to regret the decision. This speaker does pretty much everything right for my tastes and music preferences. Okay, if you put a gun to my head and force to me to share just one thing I wish was better, it would be a more airy presentation and little bit more open on the top. But otherwise, it’s hard to find fault with this speaker.

My room is 12 x 13 with almost 20 foot ceilings. Just like my friend, I’m limited on positioning options -- I can only pull out the speakers from the front wall by a foot at most. Another restriction (spousal commandment) is that I have to sell the 30.1s first to obtain the funds for the next purchase. So I won’t be able to buy something else, compare, and resell the one I don’t like as much. Secondly, I only want to buy used and well-known brands. The idea is that whenever the next upgrade itch strikes, I should be able to sell the speakers without losing more than 10-15%. And the final (whew!) restriction is that I have to be able to drive them with a tube integrated amp. I’m planning to buy a Qualiton a20i next month. This is the smaller brother for a50i which I also own.

So what do you guys think? Is this an ill-conceived, wrong-headed idea? Feel free to talk me out of it :)

If not, I would love to hear from people who have moved from 30.1s to another speaker in similar (or lesser) price range and are happy with their decision. An obvious next step is to move up to 30.2, but I’m not sure if it’s worth paying an extra $1000 or so. Or maybe it is that much better? C7ES3 is another option, but I fear it might be a little too much on the warm/lush side with difficult to tame bass especially when placed so close to the wall.

Another speaker I would love to try is the Fritz Carrera BE, but again I don’t want to buy new and I don’t see them in the used market that often. I know they have a 30-day return policy but that’s not the point. Knowing myself, I would probably end up selling them after a year or two, and don’t want to take the depreciation hit.

Proac Response D2 is another option, but I fear that it might be too forward for my taste, especially in a smaller room. If someone owns one and disagree, please chime in :)

Thanks in advance for your valuable advice!

Coincidentally, I am on the cusp of probably upgrading from my 30.1 speakers. To be clear, I do like them quite a bit, and they sound excellent in my system, but I will be moving to home with a larger (though not very big) listening space, and am also very close to upgrading my amp.

The other reason for the likely change is that my musical tastes are eclectic, and while some (e.g. jazz, vocals, small classic ensembles, etc.) suit the 30.1 very well, others, such as soul and funk, my first loves, do not. So, while I would prefer to stay with a stand-mounted speaker, I would prefer one that would be more versatile, without losing too much (if any) of the mid-range magic that makes Harbeth so attractive.

I expect that some in my position might be inclined to step up to the HL5+, but I'm more likely to try something outside of the Harbeth family.

I auditioned the Marten Parker Duo recently, and will soon be doing the same with the Triangle Magellan Duetto, and (German) Fink Team Kim. They are all quite expensive, so I doubt that the OP will consider them, but they are very high-quality speakers that should fit the basic criteria that I am seeking.
If you like the M30.1s so much why not keep them and tell your friend to find a speaker ? Why would you take a chance buying another speaker that you might not like and then have to sell them? BTW, I have owned the M30.1 and the C7!
You're local to me.  Come hear the Rosso FIorentino Pienza and Fiesole.  The Pienza are currently at Part Time Audiophile for a review but they will be back at my house on October 16 for an audio meet.  Maybe its an ideal time for you to come out?
One of the models from the Spendor Classic range, or better yet, a gently used example of one of the models belonging to the previous iteration.