That's basically what I did. All together was well over a 4 hour boil.
if you wanted to shorten that time you can boil in a vessel that is wide and shallow allowing faster evaporation. that is the part that takes so long and it's not doing anything for you but wasting fuel. once the water concentration gets low enough the flavor development is fairly quick.
So... if I could acquire a hugely-oversized wok and a powerful burner, that might just work. Although it would require a lot of stirring and watching.
at a 5 gallon batch scale when you are only boiling down about 1 gallon you could do it in a big roasting pan on the kitchen stove.