Rather you'll have an independent piece of work that borrows some OpenACS 5.0 components.
Which will make it of much less direct interest to the community. I'm doubtful we'd even include it as a contrib piece. Of course the code you release may well form the basis for the building of a true OpenACS 5.0 application.
I'd urge you to engage the community in the design process if your goal is indeed to build an OpenACS 5.0 application.