I agree, our reseller only offered us the tip of the iceburg about the program. When it has come to attempting to customize it for our specific company standards, I have found very few resources to help.
One of the biggest issues we have is in dealing with styles. We didn't know that we needed a course on AutoCAD Architecture as our base to MEP! And the available resources on Displays and Styles (both in the form of Users Guides, and available tutorials) don't really define enough to get us what we need: plotted project drawings that are consistent with industry standard.
I really think AutoCAD MEP needs to make use of a user's panel, with several representatives from each discipline, and LISTEN to what they NEED. And then actually implement the changes requested!!!!
I also found that the AUGI website had some good tutorials for OLDER versions of MEP (back when it was part of AutoCAD Building Systems, or ABS), and they may give you some insight. The forums there for MEP are also full of some good folks who can help with specific things.
We've had this same problem ever since trying to incorporate ABS 2007 into our work flow. Now, several versions later it is still extremely difficult to bring new users on-board because they just don't have the detailed task guidance available for what they actually need to do day-to-day. The reseller training barely skims the surface and is more of a key features advertisement than a how-to instruction session.