For what its worth:
I took my entire panel apart for a good cleaning. Dust was on everything, even the sealed areas behind the Gen1&2 and 4x4 lights. None of the bulbs were out though I thought they all were. Truck may have been in Iraq at some point...thats about the only place I can see that talcum powder like crap getting in every thing.
Anway, I tried the LED little replacements from autozone since I didn't want to ever take all that stuff apart again. I say don't waste your time, at least on the speedo/fuel gauge. I painted the backing with gloss-white krylon and its still barely visible....not much better than when it was covered in dust. A blue LED is great for the high-beam indicator though and reds would be good for the other idiot lights. But since those are rarely on, they probably didn't burn out on you either
That said, the stuff I picked up in the "carolla patrolla" section of the big store is probably garbage by chinese standards. LEDs can get way brighter than these things were. One could probably find some good 12V red or whatever LEDs and solder them to the base of your burned out bulbs. Or run a little bit of wire from a DIY socket adapter and have some mini LEDs project onto the face of the gauge. If using a 12V high-power LED the dimmer should give you some control as well.
I'll see if I can find anything higher power online and take some pics. It may be the kind of thing where a group buy from digikey makes it economical. Eventually I need to get in there to replace the whole gauge face anyway and I think I spotted one in a junk yard last week.