From reading around, seems that 1.5" spacers (fred's) are the thinest I can go with new studs. I've seen spacer to 1/2" with no studs and then it jumps to 1.5" with studs. Anyone seen 1" with studs? Don't care if I have to cut factory studs to shorten them.
As of this evening, I have inner steel and outer with 245/75/16 that just barely touch. If I stayed steel, I'd do a 1/2 spacer. However I have the truck at the tire shop tonight with KMC XD rockstars being installed. I'm pretty sure the thicker rims will not allow the factory studs to take a steel rim, 1/2 spacer, and the thick alloy wheels. So, if I could find thin studded spacer like 1", that would be sweet.

post pics !!

http://www.customduallytruckaccessories.com/images/spacer.jpg
http://www.customduallytruckaccessories.com/images/hubcentric-spacer.jpg
http://www.customduallytruckaccessories.com/images/spacer-1.jpg

I know Fred will not do 1" spacers as there is not enough metal when all is said and done.
1-1/2" is the narrowest he does and he is hands down the best in the business.
Dan