A few years ago I started working on a refined approach to business analysis and system design to use with Apache OFBiz and other custom enterprise system development projects. This is based on my years of experience doing this work, starting as a developer often frustrated by inadequate and frequently changing designs, and non-existent or ineffective requirements, and later taking on consulting and active management for dozens of such projects.
The material I originally wrote was cobbled together and never cleaned up, but now I have written a book on the topic and it is available on Amazon.com:
Here is a blurb about the book: "HEMP is an agile approach to business analysis and system design for end users, project managers, business analysts, application designers, software architects, application developers, and quality assurance professionals. HEMP complements agile software development methodologies with an equally agile approach for gathering and documenting business requirements and producing system designs to drive application development that will meet the needs of end-user organizations. The practices and artifacts in HEMP are applicable for building new systems as well as customizing existing ones. HEMP is agnostic to programming languages and application frameworks so can be applied regardless of technology preference. This book includes case studies and numerous examples to help you understand the context of recommendations and how to apply them."