AR-LST wanna-be?  Or, everyone wants LST’s.  Or, do most AR people dream of having LST's?
However, there are folks out there that will do almost anything to have or approximate and set of LST speakers. We've all seen home-made versions, if not do a search and see for yourself.  Years ago before I acquired mine, I too dreamed of making a pair. 
At the time,  in 1972 the problem was how to seek out all of the required raw speakers. I wasn't even pondering X-over's.
The more I though about it, the more it seemed ‘not-do-able’. Fortunately, I then acquired mine in 1987 and dispenced with such mental wandering.
Before that, I lived in constant frustration about NOT having AR-LST's. Regarding these seemingly wanna-be constructed big boxes, for obvious reasons, I don’t think they’d measure up to the quality of sound that emanates from ‘real’ LST’s. Though, being a speaker loving type of guy, I'd still be curious as to how these seemingly well and probably home made boxes do sound. In the mid 1960's I attempted a few self made speaker boxes but, the attempt simply ended in frustration and I gave up due to being 16 years old, I didn't have the where with all or correct tools, measurements or raw speakers like AR was producing. At that time, to me a X-over was a simple capacitor. In 1968 I did buy two pre-made typical ported speaker boxes (about the size of 3a's) on Cortland Street on 'Radio-Row' in Manhattan along with Jensen 12 inch drivers that I ripped out of my Fender Bassman Amp, and two horns with one capacitor. Results? Not what I had hoped for. Admittedly, whom ever constructed these did a decent job and the raw speakers used aren't bad ones. Overall a very good effort and I'd still be interested in how they sound. The builder apparently had a good idea of what these are and their operation, while, I'm sure they knew of the LST.  I'm thinking these might have been good in a small club. But, as mankind would have it, 'where there is a will, there is a way.'  If it were my project, I would've chosen different drivers but, hindsight is always 20/20. But, like I said, these may have been built for nite-club use.