I have also been looking for a good web clipping solution.
Could you say a little more about the specific functionality you’d like?
MarginNote already has a way to save web pages as PDF files. What features of a webarchive would you like that web-page-as-PDF is lacking?
I can see a clear use case for a way to simply clip some text from a web page and somehow add it to the MN database with a URL to the source (note sure of the best form to save it, though). Saving the entire web page or saving it as a PDF file may not be desirable. In any case, I’m curious to hear the specific use case you’d like to see.
Personally, I have not seriously considered MarginNote as a system to manage web clippings, because its support for document management is very weak. We customers have been asking the MarginNote team to address the issues with document management for at least a year now, but I haven’t yet seen a statement from them about what will be done and no timeframe for any decisions has been offered.
Given the lack of any clear commitment from the MarginNote team, I’ve been investigating other apps.