Microsoft Great Plains is main Microsoft Business Solutions product, targeted to mid-size companies. Currently Microsoft is in progress of transforming several ERP products it has: Microsoft Great Plains, Solomon and Navision into several business suites - Microsoft Financial, Microsoft HR, Microsoft Manufacturing, Microsoft Logistics.
These suites may be (in the future) put together and work for your company as integrated ERP solution with web interface (Microsoft Business Portal). If you are midsize company with some manufacturing - you should make the research on light manufacturing packages available on software market. In the case of your commitment to Great Plains (if you use it as your accounting system) you should probably first answer this question - do we need full featured manufacturing or we should implement just bill of materials and have missing functionality be filled with custom Crystal Reports and light Dexterity customization?
And one more thing to consider - Microsoft Manufacturing will be more likely build on Navision manufacturing base. If you have process manufacturing - you should not implement GP manufacturing - it is discreet manufacturing.
If you answer yes on most of these questions, you do need manufacturing
Now - this is what you can have in Bill of Materials
With Crystal Reports you can have this information, having just Bill of Materials
Good luck with your research