There may be such an amimation converter, I don't really know. How far have you looked?
CDXL doesn't offer the sort of compression ratio that would make it achievable unless you use very low quality.
Several GB of DVD footage would end up as several tens of GB of CDXL and would probably take an age on a 680x0 amiga to convert.
Why dont someone make it?
GCC and VBCC are free to use. If you want something and nobody else has produced it, make it yourself.
Before anybody says it, excuses such as "I can't program" aren't acceptable since:
1) If you want something badly enough, you will learn.
2) By doing so you will advance your own skills and be giving something to the community. We need more developers!
3) It has never stopped Microsoft ;-)