Some parts of your post read a little like "I have a relational hammer, so the whole world looks like a Codd defined nail":) Please take that in the humourous manner in which it was intended. If you do have any interest in looking at an alternate viewpoint, you might like to read The OODBMS manifesto. The word "manifesto" kind of put me off reading it the first time I was refered to it, but I bit the bullet and read it anyway and was glad I did. It's not a that long. A hour or so should do it as a first pass.
In response to this, and some other OO manifesto thingy, Chris Date and Hugh Darwen wrote The Third Manifesto, which details what a truly relational DBMS should provide. SQL does not adhere to relational theory, and so comments to the effect of "I've used relational DBMS's and they don't do what I need ..." are incorrect, because AFAIK there are no truly relational DBMS's.