Re: Simple urls for IVS without extra IP addresses
This could be done with a "Redirect" on a apache server.
You could host your portal.customerA.com on a apache site, and then have apache redirect the user to the portal.company.com/customerA.
You also might be able to do this with a meta-refresh=0 tag ( http://en.wikipedia.org/wiki/Meta_refresh ) on a IVE custom sign in page. On the sign in pages config section you could enter the portal.customerA.com/ virtual host, and then select the associated custom sign in page. I haven't tried this but it is worth a shot.