Rino,

One more tip. Use the screentone patterns from Crazykira on Deviantart. The link gives you some examples, but if you search her (?) work, you should be able to find many more similar patterns.

Give them the colour you want, and make the background transparent. You then have a texture that consists of "blobs" that are either 100% transparent or 100% opaque. SH3D and the Sunflow renderer should be able to handle those patterns correctly. If you can't find what you are looking for, I have a series of dotted patterns ranging from 10% to 90% transparent.

EDIT
Try this link: http://browse.deviantart.com/?qh=&section=&global=1&q=patterns
END EDIT

Hans