I'm just wondering if you actually need multiple accounts. Can't you put all the files in one account? And then put all the different websites in different folders, with an index.php in the root public_html folder linking to each of them, and if necessary protected with a password. If you really need seperate accounts afterwards, you can just go on with your original plan.
A few years ago I was participating in a course to learn web designing basics, and they used exactly the same setup.
PS.: They weren't using x10hosting, but another host.
PPS.: Could someone confirm if this is allowed on x10hosting?