Custom Speedometer Work

[oasis]

The way the gauges are going to be in my car for the foreseeable future, I want to tweak my stock speedo.

I want the speedo to appear similarly to the way it does currently but with two differences:
(1) I want the speedo to have a maximum of 120 or 140 MPH -- doesn't really matter which as long as it is greater than 90 MPH.
(2) I want the updated speedo calibrated to my current front tires. My current speedo is roughly 5% off (reads 60 but actually is about 57).

Who does this sort of work?

I wouldn't mind the odometer being reset to zero, too, but that is not so imperative.