That is neat, prevents the DIY-ers from having a nightmare; well, the ones that don't do much DIY.
I had a reefer on RC retrofit a Tek 8xT5 with DIY LED center strips, the full length; it was one of the old fixtures I had as a project. Glad someone gave it new life. He used an IceCap 660 to overdrive the four T5 lamps to about 80W each !
Now, a ball-swivel mount for Kessil light, that would be awesome so you can point your Kessil where you want to.
I bet you can squeeze an AI Vega or similar rectangular LED fixture inside a Tek, either six or eight bulb unit. And that reminds me I still have an old Tek, but a 36" six-bulb.
I picked up an older Current USA MH/PC from a member here and initially that's what I have in mind; in the end, might be just another Frankenstein project, you know, dead before gets life...
A guy on RC added ball-swivel mounts to his Kessil A150, he said bought them from Adorama.