just go to a junkyard or look around online for a different cluster with rpm gauge, it's pretty easy to find.
i like to think about it like this, a possible mod, and while you're at it you can do other mods!
if you change the cluster out, since it's already out, it would be easy to do the following:
1. convert to LED bulbs/replace any burnt out bulbs
2. cluster bezel overlay
3. paint the needles
4. you could possibly even get an alarm installed in the space around cluster if the brain is small enough (aka Stealth install) and i guess if you can find a mobile installer