I recently had to costume someone with a 57” chest and 57” waist, and looked many places before giving up and just going to Amazon. I freaking hate using them so much, but they do have a decent range of larger clothing.

Did a really quick search and this popped up immediately. It's always worth checking to see if any of the Prime options have a "used but good/like new" option for sale - that generally just means someone bought/returned without wearing, or without wearing more than once, and the discounts can be huge. I have frequently done this to pay $20-$35 for nice leather shoes for my actors that would have been $100+ otherwise.