Rotor chainrings do. They sell them oval and round. It may be rare, but Shimano 9100 or Dura Ace would be the ones most likely to have the larger rings past 53T. A quick search showed places selling the 9100 crank with 54/42. Not sure why you'd want the 46 instead of a 42, but that's what they seem to sell. You'd have to replace the inner ring if that's what you wanted.
Depending on what the companies offer, your limitation on max chainring size will wind up being how high you can raise your FD if running in a 2x setup. You may have to buy or make a shim to raise the FD more. I think one of the British time trial gear websites sells such a thing. Drag2zero, Aerocoach, or something like that.
Otherwise, your q-factor and chainstay may be a limiter on largest ring size. Some bikes start having issues above 53T and 54T. Then you'd have to shim the ring.
Most of the megasized TT bike chainring setups you see are on 1x setups. So no FD height issues for the big boys in Britain running 60T rings. Geeeesh that's huge.