It used to be that you could "safely" bot more than one account per HWID/IP. Not so much anymore. Overlapping inputs on the same hardware is a dead giveaway, no matter what method of botting you're using, even simple macros like I use. Unless you are suicide botting/goldfarming, you are wasting your time buying servers with massive specs. However, if you must, go dedicated only, split the server into several VMWare or Virtual Box instances with a pool of private proxies.
These days, you should get multiple low-cost KVM machines with at least 2GB of RAM when botting multiple accounts. Sure, you will end up managing 50 smaller servers, but the benefits of total separation in your bot farm is well worth the investment.