Interesting current research on SharePoint from AIIM: SharePoint Strategies and Experience. Among other items of interest, Analysis on pg 19 shows 65% of users plan to add or have added on BPMS functionality and 30% plan to or have added Case functionality from 3rd party vendors.
I feel your pain. I never had any good luck with this kind of thing, either.
So happy to find out I am not by myself!