Management Pack Whitepaper by Silect
Silect Software have written a whitepaper which targets Management Pack development from simple MP's containing a few rules, to complex ones using scripts and State view components.
This whitepaper is an excellent starting point for anyone wishing to develop a custom Management Pack. Whilst it doesn't cover the technical detail on how to create a Management Pack, it does advise on the processes and procedures that should be created and undertaken to ensure that your new Management Pack is not only developed quickly and efficiently but also that is is appropriately managed after deployment.
There is also some really useful information about how Silect's Management Pack Studio software can assist in the process of developing a Management Pack.
So in conclusion, if you are planning to write a custom Management Pack, regardless of size and complexity, I would recommend to take a look at this whitepaper.
Request a copy of the whitepaper here: http://www.silect.com/products/whitepaper_request.htm
Andy