The limits on tenants are soft limits and should be extendable by reaching out to them.
At one point we had a dozen different Amazon accounts to keep everything separate. Thankfully the business model was crap, so if resolved itself.
Did Amazon mere said, "you are doing it wrong", without an explanation? In retrospective, do you think you could have done better? I'm looking to hear the lessons you learned, so may be, I don't end up making that mistake ;)
S3, I think they did up the bucket limit on request, but maxed out at 1,000. That was years ago though.