Semi-manual tranny?
 

Would it be possible to add some semi-manual control to the auto tranny on these cars? The upshift is controlled by having no vacuum on the transmission, and down by the kickdown switch, right? So would it be possible to have some buttons to push when you want it to shift? Like wired to the kickdown, and a valve on the vac line? I'm not talking complete control of shifting whenever, but when your RPMs are near the shiftpoint, but it hasn't shifted yet..

Vacuum controls shift firmness. The bowden cable controls when it shifts.

if you want semi-manual, just shift the selector when you want to let it up shift.