You do not seem to offer domain registrations.
Without domain registrations you will be missing a significant number of potential sales opportunities.
"Domain Parking" is a necessary service as it helps you to build and inventory of domains that could convert to hosting accounts over time. Our experience is that 20-25% of parked domains convert to hosting accounts within a year.
I recommend that you set yourself up with http://www.opensrs.com
and ask for Doug McDonald. They are the only registrar that I am aware of that will not try to steal your customers.