Single site WordPress installation on a web hosting agency

Hello,

I am trying to create a web-hosting platform for wordpress sites. I managed to do it with Pro Sites plugin, and it seems to work fine.

My problem is that it is only possible to host sites in a multi-site WordPress installation. The site admins (my clients) cannot install new plugins/themes – they need the super admin to install it for the whole network. Also, if they wish in the future to move to another hosting, they cannot do it, because there site i a part of my network.

Is there anyway to allow a single site installation for a client, outside of the network, so he can have an independent “normal” WordPress site, and he is free to install plugins as he like, or even move the site to another hosting if he wish to do so?