"I'm not saying you are wrong". That's good, because it was not I who said it, but rather Wendell Diller, in a press release. Have you bothered to read it? Don't blame the messenger!
Whether I or anyone else agrees or disagrees with what Wendell said is not the point, and should be of no concern to you. But I would think what Wendell---the Marketing Manager of Magnepan---has to say on the subject would be of some interest to the owner of an LRS. I don't own the LRS', and it is to me.
The real best choice of subs for the LRS would be the bass panels of the Magneplanar Tympani loudspeakers. But they are long-out-of-production, huge (each of the two bass panels of the T-IVa is 6' H x 19" W. A pair is over 3' W! And that's just for one channel!), need LOTS of power (one Tympani owner on the Planar Speaker Asylum powers his T-IVa bass panels with 2,000 watts a side), and are rarely available for sale.