Minoura makes several different models of bar clamps for 1 or 2 cages, including QR models. Many bike shops carry these. Other mfrs also make them, and cheap cages with clamps attached are commonly on display too.
But none have the cachet of TA cages. And one good thing about the TAs -- or, if you prefer, problem with the alternatives currently manufactured -- is that the TA cages hold the bottles low, while the alternatives make them stand up too high above the bar, IMO. Not a horrible defect, but one that does make the cages tend to rotate downward if they are not clamped very tight, and one that makes removal and replacement of the bottle a bit more awkward.