I hope you don't expect unbiased contributions here: Take OpenACS! ;)
What you want to do is (mostly) there with OpenACS: the upcoming 5.0 release has the features you are looking for. Needless to say some are in a fairly rough shape, and some of your requirements don't make sense yet to me. E.g. what is "workflow applications"?
There is one beautiful thing about free software: It is free! You can download the whole stuff, install it on a box, and configure it to your needs. The only investment needed is time.
Thus you can form your own (less biased) opinion based on your needs.
