It is against the Terms of Service to own more than one account per individual.
As Skizzerz said, Addon Domains are the solution to this, since they allow you to host more than one websites on one account.
In your post, you said you wanted more 'space'. x10Hosting offers you unmetered space, meaning that you have unlimited as long as you follow the Terms of Service. Therefore, there is no need to worry about 'space'.
You can create an addon domain by purchasing (or signing up for) a domain such as .COM. If you do not want to pay, there are free services around like
CO.CC that you can use for a domain. After you buy/sign up for a domain, you will need to find an option to set 'Nameservers' up; it should be somewhere on your domain registrars website. You should add the following nameservers:
ns1.x10hosting.com
ns2.x10hosting.com
Then, go into cPanel, click Addon Domains, and fill in the form. It can take around 24 hours for the domain to become activated. If you have any further questions, feel free to ask