Yes indeed, last week I been in manufacturing implementation with one of my existing clients, they wanted to implement BOM and Manufacturing order processing modules of the GP Manufacturing, they had every thing ready (Bill of materials, Standard Costs, and all other related issues).
Their policies are clear, to use Periodic costing for all material and overheads. First day I did imported the Bill of Materials, virtual routings (as the client is handling the overheads as items with variables in the bill of materials), and finally adjusted the initial standard costs for all items using macros.
Manufacturing setup in the second day took no longer than 2 hours to adjust all the parameters and defaults, then I started testing the functionality, I tested as much as requested and compared the results with their current calculations and all was completely matched.
As the client accountants and IT department were all professionals and aware of all GP processes (they are GP customers since GP 7.0!) the training delivered within 6 hours of the third day and the guys started the manufacturing process directly.
Well it could not be considered a “manufacturing implementation” as they only implemented the financial side of the manufacturing (BOM and MO modules), but it was the fastest implementation I ever made!