If you are handy with a soldering iron, you can change the LEDs used to light up the cluster.
You can also change the LCD illumination colour using the same technique (I.E. change the LEDs on the board behind the LCD panels to the colour that you want)....
The only thing on the SV6 cluster that is difficult to change the colour of are the needles. (They have the red backing on them, so really you can only use RED illumination on them)....
The LEDs can be bought from eBay pretty cheap (around $10 for enough to do a couple of clusters)
The best colour I have found is white, as it makes the LCD and cluster very easy to read at night.
The following page show what is involved (including cluster removal and disassembly).
It also shows an Omega cluster with a white LCD panel, and blue cluster illumination, as well as a HSV cluster that was in the process of a conversion, from red to white illumination..
Hope this helps
www.carmodder.com • Changing the Cluster Illumination for the Holden VE Commodore