From the "Don't Try This At Home" department:
Once had a really long pull of 500MCM's thru a really ugly conduit run, and the Greenlee tugger wouldn't tug any more (wire half way in). So my boss, great guy that he is, got us another Greenlee tugger. Not a super tugger. So what could we do? We used 2 tuggers in-line and finished the pull.
I chained both tuggers to a 4" piece of heavy sprinkler pipe, and mounted that on unistrut standoff's to the concrete deck with about 6 sets of anchors. Pull went OK, but we were overstressing the rope a bit. I had arranged the entire assembly so i could handle the rope from behind a CMU wall (thru a doorway), just in case it all came loose, or the rope broke.
Note to anyone else dumb enough to try something like this: ONE AND ONLY ONE turn of rope around the back tugger's capstan. It was actually fairly easy to control.
Not the smartest thing I've ever done, but it worked.