Sort of off-topic, but in that train of thought, wouldn't be be really easy to make a sega shifter clone via a regular old bat joystick?
You'd probably need a longer shaft and a latching system, but I don't think it'd be terribly hard to modify. The diagonals would be the shift positions of course. For some reason the price of the shifters has really went up... not sure why.
I've actually thought of doing this with a spare x-arcade stick I have.
The Sega shifters have a plastic wheel between first and third and another between second and fourth.
The bottom of the shifter rod travels around the each side of the wheel and feels like it has resistance as it goes around the widest part, then "slips into gear" when it gets past that point.
I was thinking about trying to add small wheels inside the existing x-arcade joystick body so it would require minimal work.
The x-arcade stick even comes with four levered switches that could be mounted to register the gears.
Haven't posted about the idea because it really needs pics/diagrams and I haven't had time to make them.
On the non-cheap side, lately I've been kicking around ideas for what an "ultimate shifter" would consist of.
The best sim racer shifters are over $100 and I think we should be able to build something much better for that price.
I really like the ferrari f355 shift gate, but ferrari looking corvette knobs are much cheaper and have reverse on the right instead, so I'd probably flip it.
I don't care for how the ferrari shifter sticks up so high above the gate though.
Looks a bit like bob barker's microphone.