Hello
I appreciate this thread is a couple of months old however I wanted to post to let you know what I use...
I use a wordpress plugin called MainWP it's similar to InfiniteWP only it's based in Wordpress. It's free and has a whole host of reasonably priced addons. I used to use InfiniteWP only I wanted a solution with just one login that would allow me to update my sites (about 50 at the moment), manage projects and tickets and allow my clients to login to check.
So here's what I have done, I have installed wordpress on a subdomain with the following plugins:
MainWP and various paid plugins to manage my clients sites
WP Project Manager PRO - to manage my projects, this also includes frontend shortcodes so clients can check also.
For the ticketting system I search and tested so many free and paid solutions however none of them did what I needed which was to import emails from an email account and allow my clients to reply to tickets that the system will then import. So for this I installed OSTicket (open source) configured it and then used the plugin 'Key4ce osTicket Bridge' which allows you to manage tickets from within wordpress.
For Document management I use User File Manager plugin.
I have set this all up so that when my clients browse to my subdomain they get the wordpress login (customised of course) and then once logged in they have options to view their projects, tickets and documents.
It all seems to work perfectly at the moment.
As for charging clients for updates, I include this in the cost of hosting.
Hope this helps anyone….