I have a small web design company, so all of my clients are hosted by other companies...since I am a webmaster for most of the sites(90+ static, resume size sites(5-10mb)), I wanted to get a dedicated server in which I could collect hosting fees and maintenance fees. I am fairly unfamiliar in sys admin, but I can learn quickly.
My questions are:

1.Are the duties of running such a server still too complicated for a newb?if so what should I learn? which book should I buy(i.e. Linux Red hat 6.3 bible)?
2.If I will maintain all of the accounts,
do I still need to pay to license multiple plesk or ensim panels? could I just do it from 1 panel.
3. will the dedicated(unmanaged) provider give me enough support to get started and my domains transferred and running smoothly?
4.Would a virtual terminal , like wells fargo be sufficient in billing and transferring funds to my account in an expediant manner?

I think the best bet for you would to get a reseller account, there are some good reseller companies here. That way you still get to collect your fees and pay a lot less. It will require less maintnence and you wont have to deal with all the technical stuff.