Ok, i think I understand a little better now, but i'm still a little unclear on the final product you have in mind. Something like Bidule, but less proprietary?
I've never been a fan of loading VSTs in Csound. i always found it somewhat flaky, and a little troublesome. I know it runs on Windows, but have you been able to get Csound to load VSTs on OSX? Cabbage will be able to load VST plugins in the future. So it will be possible to mix VST plugins and Csound code without having to get Csound to load the VSTs. Are you familiar with Cabbage Studio, which is currently being absolved into Cabbage 2, but that lets you patch together effects and instruments in a modular fashion. One doesn't even need to know Csound to work with that.