Those are the low quality dial up numbers. They are not being reasonable. Any business that has such sever internal data rate problems can't be long for this world as this would be the poorest of all possible managed IT departments.
Maybe if you created a 160x120 file at about 10fps it might be passible as a small postage stamp size at 50kbps.
Make sure they don't mean 50KBps which would be more like 400kbps which is still severely limited but might be a limit set by very conservative IT departments who don't understand the importance of video in internal communications.
IT people in general are clueless about streaming video across networks and the internet. We deal with this constantly. What generally happens is we deliver web or network ready compressed files and they end up getting recompressed by somebody to a different size, codec and data rate, and if it's 16x9 it usually gets resized to 4x3 (or vice versa).... even though we've given them what everyone agreed upon.
It's incredibly frustrating and quite amazing considering how pervasive video is online. That said, streaming video can also be incredibly complex and in the corporate world, the end-users hardware and software configurations can vary wildly. We've encountered situations where the client loudly complained that the videos we sent don't have sound...only to find out days (and hours of troubleshooting) later...that none of the workstations in the company have sound cards.
Or on another occasion, deliver a client requested Quicktime movie and again get complaints that no-one except for the Marketing Department could play it (see where this is going?). I figured this one out quickly. The marketing department was all Mac...the rest of the corporation was PC...and weren't allowed to install third party video players (i.e. Quicktime)...so they couldn't play the .mov file.
I could go on for days....but the only solution is to give them choices and give them several versions and make your recommendations...then let them decide what works and doesn't work. Oh yeah...charge accordingly!