Like somebody else said, the seemingly strange sample rates of some of the more professional boxes are meant to deal with "pull up" and "pull down" situations encountered in post production. On a film shoot, most people shoot (record) audio at 30 fps, with a set time code generator acting as the master. The camera operates at 24 fps. During telecine, in order to frame-match NTSC video speed, both the camera and the audio need to be slightly slowed down in order to sync. That's what gives the .01% difference. Now, you may ask, why would you record at 48.048k or 44.156 when you're pulling down in post-production. The answer is that for movies t hat are never going to be re-released in theaters that it's easier to just record audio at just slightly faster than film speed, knowing all along that the final output will end up at video speed (.01% slower again) and be more compatible with most editing systems.
In other words, if you shoot a movie at 48.048, you don't need to pull down to 47.952Hz during the editorial process. You can, instead, submit video-speed audio that will enable just about anybody to work on the movie without the need of high-end equipment (TDM Pro-Tools, or Nuendo with Timelock and Blackburst). If you have any questions about this crap, please email me at stuart@soundbreeder.com