I personally find it more sensible and charming than Maddox. I didn't realize this name was so uncommon, because I'm pretty sure I've met a kid called Madoc.
Madoc (Madog) ab Owain Gwynedd was a Welsh prince who supposedly sailed to America in 1170. Where I live, there are legends of White Indians who spoke a dialect of Welsh. They are supposed to have descended from Madoc and his people. It's interesting to read about, but nothing has been proven.