I honestly don't know of any open source docks for Windows... As for portable, a lot of the apps here have little to know system footprint. Standalone Stack comes to mind, but have a look at the forums and try them out to make sure. I know that AveDesk is also configurable to be installed and isolated to a single folder, and although it's not exactly an app from here, Rocket Dock can very easily be configured to be portable by checking the "Use single user" checkbox, or something like that. I hope this answers your question!