There is not one complete box set as far as region 1 dvds are conserned but the way to condense your collection into the most region 1 dvd box sets as possible without any repeats is this:
1)
http://www.amazon.com/The-Godzilla-Coll ... 293&sr=1-12)
http://www.amazon.com/Godzilla-Boxed-Se ... 473&sr=1-73)
http://www.amazon.com/Godzilla-Collecti ... 556&sr=1-3that is as much i believe you can do as far as box sets go, the rest i think you just have to buy seperately (the sony box sets with the showa godzilla films have gotten pretty expensive though since there now out of print so you might have to act quickly on some of these box sets before there all sold out)
now you will still have the buy all the dvds, but if you want to condense all of your boughten dvds so they take up the least amount of space i suggest this:
http://www.roberthood.net/miscellaneous/index.htmif your interested in this i suggest you buy the covers from usplastics (source 2 on the website). You will have to buy a couple sheets of legal size paper, download gimp 2.6 or anything like this and dont forget to go to print preview and set it to landscape so it prints long ways... I did these self made box sets and i got pretty good results so i would recommend doing the roberthood boxsets