I have had similar thoughts due to the location of the rotors on my Simagic GT1-R as I have to lift my hand off the wheel to use them. It's sort-of ok since I don't really use them for in-race adjustment, but even so I'm considering making something myself and recently saw someone post their own design on reddit which piqued my interest:
View attachment 530727
I like that there are two rotors at the top similar to the Formula style wheels. I haven't seen a wheel button plate with this before. I'm also thinking about having buttons on the back of the box so I can operate them with my index finger. Essentially I'm hoping to have buttons/rotors in the upper half only. I'm still looking to see if anyone sells anything like
this, but no joy so far.
The design for the above is available for a small fee:
https://pokornyiengineering.com/collections/diy-designs/products/gt2-plate-diy-files