Miika Hämäläinen is in the very early stages of developing some exciting new features to enhance the realism of interactions with fluids, particles, and animated objects.
"WetMaps"* allow for fluids to leave surface effects on objects contacted:
"Mesh Paint"* allows you to "paint" a texture with other animated objects or particles:
*tentative feature names
However, this project is still in very early stage so there is no downloadable build or patch available anytime soon. All depends on how much time I have and if I manage to keep motivated. :)
Please visit the developer's website for more info and to show some support to help keep him motivated.