First, the success: the MadCatz MC2 wheel for PS2 worked fully in digital and NeGCon mode when using the following setup: bohoki adapter + amiga-->PC gameport adapter + Wellingham PS2-->amiga adapter + Mad Catz wheel. Wheel, pedals and shifter worked after on board setup and minimizing deadzone. One note: the wheel is supposed to have re-centering, but this did not seem to work. You may have a slight pull to the left or right with my setup, like a car out of alignment, since there are no trims and I had to adjust the motherboard pot. This should also work with the Masterplay Clone, and since the Masterplay Clone has trims, you can probably fix any left/right pull. The NeGCon mode seemed to have variable steering intensity depnding on how far you turned the wheel, but not sure how "analog" it can be with this setup.
Maybe someone can comment on how well the actual NeGcon controller works with Pole Position on the Masterplay clone with a PS2 to 9pin adapter, since I don't have a Masterplay clone. Also, if it can provide true analog with the NeGCon or Mad Catz MC2 in NeGCon mode in the Masterplay Clone's paddle mode.
The third mode on the MadCatz MC2 is analog mode. This is designed to make use of in-game setup, so nothing works with my setup in this mode.
Now for partial success:
With the Innovation Smart Joy PS2-->PC gameport adapter, I was able to get the MadCatz wheel working with the following setup: bohoki + Innovation + Brooks PS3-->PS2 + USB spliiter cable with one side for power + powered USB hub connected to power lead and PS2--> PS3 adapter coonected to other lead + Mad Catz wheel.
The first issue here is that the wheel really wants to stay in analog mode. You press the mode button and it flashes to digital and back to analog over and over. Analog is the mode you do not want, because the steering works, but the pedals do not. You need to use a button for gas and brake. With A LOT of patience you might get it to stick in digital or NeGcon mode and then the pedals will work. By "a lot" I mean quickly tapping the mode button, 1/50 times it might go from analog to digital and 1/1000 times it might go from analog to NeGCon. You can get real analog steering with NeGCon. Not sure if there is a solution to this issue or why it wants to stay in analog mode.
The second issue is that with this setup, there is a large pull to the left and up. In this case, it cannot be centered even with the motherboard pot and nothing in this setup has trims. You can still steer it enough to play well with a slight alignment issue, but the upward pull makes it so you cannot shift into high gear.
You might be able to fix the second issue with a trimming pot or capacitor added to the bohoki adapter, but the first problem (not wanting to switch from analog to NeGCon mode) is a real nuisance and I don't know why it keeps returning to analog mode. Remember that analog mode on this wheel uses in-game setup, so the pedals would not work and, at best, you would have to use buttons on the wheel for gas and brake.