You'll need to grab one of the iterm2 nightly builds, for this to work, since coprocesses don't seem to be in the releases yet.
This will enable you to cmd-click on a filename in iTerm2 and have it launch vim within the same iterm2 window:
Click on: Preferences -> Profiles -> Advanced
Under "Semantic History", choose "Run coprocess..". In the text field, put:
echo vim \1 +\2