Grissim,
Joel over at 8weeksout likes to use the VersaClimber. He uses it for a very specific purpose--what he calls High Intensity Continuous Training (HICT). He has an article on it. A jump rope cannot be used for that purpose. There are very few exercises or machines that can be used in place of the VersaClimber. The VersaClimber is the only machine that would train the upper and lower body. As far as using a C2 Rower goes, Joel talks about it here:
http://www.8weeksout.com/phpBB3/view...=c2+rower#p822