Look into Mistfall. It would infect other executables by splitting them into basic blocks that end with some branching instruction and inserting metamorphic portions of itself in between blocks and fixing up all of the modified addresses. There literally isn't any "static" portion. Here's a mirror of the author's site, he is Russian but there's a ton of English translations and articles that are a great read.

http://z0mbie.daemonlab.org/