i know they have 3XL tees, i don't know for the 4XL :s
But you know, getting an account doesn't force you to buy anything!
And this tee isn't available for sale yet, i hope he will be, if i get lots of votes! ^^
Check out the qwertee.com website. The 3XL sizes like 28/32'', or 70cm width / 80cm length.