In large-scale, there are 2. Revell's 1/32 Huey is listed as a D, but really builds into an H. Panda's 1/35 Huey can be built as an H as well. Check mine out here. More info on the Revell kits here too.
I know there is at least the Esci D/H kit (reissued by Italeri) in 1/48. It is the best 1/48 Huey out there. Not sure of what is out there in smaller scales, I don't build any smaller myself.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
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"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell