Can Craft easily be hosted across multiple servers?
Entirely possible. There is some discussion of having Craft installed in a load-balanced environment here.

You'll want to have CRAFT_STORAGE_PATH point to a shared file system for all servers.

If you have sticky sessions enabled at a load-balancer level, then PHP sessions won't be a problem.  If not, then you'll want to set overridePhpSessionLocation to true and have the PHP session files saved on the same shared file system.