Domain Mapping – fun with Subdirectories

after reading a couple dozen threads (many too old to be any use whatsoever) and the directions a few times… I need a recap from the experts (along with a shot of whiskey nightcap and 2 aspirins). This question has been asked and answered more than a couple times but I need help with the current setup:

I have this:

example.com

example.com/subdirectorysubsites/

I want my clients to be able to do a couple of things:

1) clientsite.com goes to example.com/clientsite1/ so that browser displays clientsite.com

2) subdo.clientsite.com goes to example.com/clientsite2/ so that browser displays subdo.clientsite.com

to make it even more complicated I have SSL… which I currently force to all SSL (frontend and backend) but might have to let subdo.clientsite.com render as http://subdo.clientsite.com as well as maybe http://clientsite.com

this is a root install, I have a VPS with all IP’s being mine, but some sites share IP

so…

please walk me through it

a) is it possible with WPMUDev Domain Mapping

b) is a dedicated IP going to be necessary

c) please explain how… *

* I imagine this might be an appreciated tutorial

Thanks