Hi Music Lover,
I had the privilege of having a pair of Ellis 1801bs visiting a while back. We listened to them alongside my HT3s, and I was VERY impressed. Excellent imaging, and very natural sound. I was surprised at how good the bass was. When I saw Jim had designed a TL version, I thought that it's gotta be a winner--making a very good speaker even better.
I also own the dome-tweetered Songtowers, and listen in our small TV room. I opted for those over the 1801bs because the Songtowers' smaller footprint works better in the very limited space. They have surprisingly good bass extension--but I think you're right the Ellis would be better in that regard. I didn't have the opportunity to compare the sound of the two in the same listening session. But from directly comparing both the Songtowers and the 1801b to the HT3s, my impression is that the Ellis is significantly more "HT3-like," if that makes any sense. It's hard to describe exactly. I'd say they were more dynamic, with a greater sense of transparency maybe.
I don't think you can go wrong with either. You might want to talk to Jim for a bit. In any case, have fun!
Craig