This may sound stupid at first, but the idea might grow on you...
Since I got my 4.10s installed, I haven't gone over 70 mph on the highway. When I go to the track, I want to have it set to unlimited, but for everyday driving, I'd like to have my speed limited to 70 mph.
I'd also like to decrease my RPM limiter to 5000 for everyday driving.
Now that I'm going crazy with the upgrades, I'm losing drivability fast.
I think the speed/rpm limiter would be nice in case someone else drives your car (mechanics, relatives, etc). Every time I hand the keys to a mechanic, I get it back with A/C on full blast and the tank is empty yet the trip only reads 20 miles.
I'd also like to have control over the partially-open throttle shift points. My car shifts WAY too soon automatically with the 4.10s. I'd like it to get a little more speed before it shifts. This may not be possible, but if it is, I'd LOVE to see that feature.
Promote it as "Valet Mode" hahahaha.