Is anybody out there making front axle rebound straps?
I'm not aware of any reproduction ones. I was willing to settle for plain straps (not the sprung ones), so I went to Walmart, bought four heavy leather belts, and installed them on the front and rear. I like them, they help reduce the "ejection seat" effect on big bumps.
I believe that some of the street rod vendors offer sprung hood hold-down straps, perhaps those could be adapted to work as sprung rebound straps.
Talk to your local harness maker.
They help in cornering also. Springs would reduce their effect.