Like stated just get a closely matching year gauge cluster from a Denali or an Escalade.
I just put a 2005 Escalade cluster into my 2004 Tahoe and the trans temp gauge works fine. Doesn't do much since I don't drive hard or tow, but it does work just fine and it looks good.
Or go all out and get a separate gauge pod, mount pod and a trans temp insert and tools necessary to drill into your tranny. Your choice.