plate carriers and variants are actually constructed outside of milspec sizes for use by people of all sized. I purchased a CIRAS and had to actually melt new adjustment holes into the strap so I could get it snug enough to actually fit me and hold the plates over my torso properly. With my issued plate carrier, i had to sinch down two straps...
www.ebairsoft.com has one of the largest selection of inexpensive plate carriers, chest rigs and vests Ive ever seen. good prices and good shipping time (like 10 days from China)
These are all adjusted to the largest settings when they arrive, and would easily fit an 8 foot tall guy with ease....
You'd be surprised what you can hit when you aim.
GHK all the way.