I don't know of anyone that sells one. However, you could always buy two and combine them. for example the
Suzo Happ top-fire uses that relatively standard base. If you also, bought a
GGG Super-Pro Leaf (or Pac Pro), then you could swap the leafs from the Super-pro to the top-fire or the top-fire shaft to the super-pro, which ever makes sense. You might also, ping GGG/Randy to see if he will sell the joystick leafs separate to save some cash.