Hey Joshua,
An update. I went on vacation for a week the day after i wrote the big post. Been chewing on this quite a bit along with sorting business logic around our requirements. The program I am writing is WPF and will always be run inside the secure network of the GP user. The HUGE pain in the *** and abstraction/transformation exercise that WCF->eConnect->MS-SQL is, while impressive is just to heavy weight to be of use to us and would be an undue burden on our customers, installing web services, installing our custom web services and extensions, web services security to name a few. So, I've thrown the entire idea of WCF out the window and have gone for Entity Framework with SQL Authentication, which just kicks butt in just about every way possible accept one, stored procedure system analysis.
When getting data, its pretty straight forward, I can just run queries. However, I'm now starting to look down the wabbit hole of creating data in Dynamics. Understand that all Business Logic in GP is done at the Stored Procedure level and that eConnect is primarily trying to abstract that into a business document interface. Ran a little SQL Script today and found that there are 20,031 Stored Procs in GP2010. The naming isn't any better of Stored Procs than on Tables. Besides using SQL Profiler and system table queries to decipher eConnect, is there something out here in developer world that shows the pathway through the Dead Marshes (Lord of the Rings Reference) of GP Stored Procedures for some pretty standard CRUD operations?
Matt