Just checked out VMPrint and it's crazy! Keep up the efforts. If you/someone could get a HTML/CSS input layer in front of VMPrint that would be a killer feature? Or is it possible already?
Thank you. The architecture to get an HTML/CSS input layer in front of VMPrint is already there via a component called Transmuter. I have made transmuters to allow markdown with custom syntax support as input, and they work extremely well. Full support of HTML/CSS will be still be difficult, but a well-defined subset should be easy. The sibling Layoutmaster project also demonstrates this -- you can hand it a DOM element and it automatically grabs the styles and contents, converts them into the JSON AST, then feeds them to the engine for instant layout.
Basic text styles are ok, but things like authored pagination, page header/footer, mirrored margins, margin notes, footnotes and references are basically unsupported or need to be hacked together.