Makes sense, at least for short-term. Use variations on off-the-shelf tech, and build big dumb boosters that may not be sexy, but they
will git'r'dun.
Thing is, the principal objection to the BDB remains: Chemical rockets have a helluva lot of parasitic weight vs. their payload. I brought up laser launch systems earlier in this thread. Results of a hasty search on Google:
http://www.lightcrafttechnologies.com/newsletter.html
http://yarchive.net/space/exotic/laser_launch.html
It makes a nice near-term bridge-to-magcat launch system. Jerry Pournelle described a large-scale man-rated version in
Exiles to Glory in 1977, creditiong the concept to AVCO Everett. Take one humongous nuclear power plant. Plug in a big honkin' laser array. Train it on a target inside something that looks a lot like the combustion chamber and bell nozzle of a rocket motor. Light that sucker off. Your reaction mass is the ablative material loaded inside the "combustion chamber" plus the surrounding air and/or reaction mass you bring along. May not be as elegant as the magnetic catapult, but whatthehell, you're going to need a humongous power source for your cat system anyway...