In WHM, can you create a package that allows for multiple domains?

Looking at this, it doesn't look like it:
cpanel.net/docs/whm/Packages.htm

I want a single user account to be able to have multiple domains.

Since I can't seem to find a WHM demo, I can only look at screenshots and read the WHM docs. Cpanel demos also don't seem to have an "add domain" option, only add sub-domains, domain pointers, etc.

Yes, the setting in WHM is referred to as ADD-ON domains. This is a setting that is controlled by the user's package.

The add-on domain's files are then stored within a sub-domain of the main account.

OK, I see it. The cpanel docs say:

An addon domain is a domain name that that points to a subdirectory within your account. For example, you may want innovation.org.nz to point to business.org.nz/innovation/. Addon domains must be registered domain names that you own and configured to point to your web site's servers.

In this example, does the URL in the browser indicate that the user is looking at http: //innovation.org.nz, which is simply displaying the files in the business.org.nz/innovation directory? Or does the URL redirect and display http: //business.org.nz/innovation? Doesn't seem like a true virtual host entry.

Can a user create email aliases for the add-on domains?

It displays innovation.org.nz with the files from the other folder.
Yes you can create email accounts/aliases for add on domains.

Thanks for your answers! It was very helpful.

I think I'm going to go with DirectAdmin after all.