A Russian MiniX owner found a composite out cable that worked, from one of his media players. Hopefully they will be shipped out together with newer batches of MiniX boxes in the future.
There is no store to get these cables, as far as I’m aware of, so hopefully the manufacturer sells them to the bigger stores as a spare part (Dealextreme, Pandawill)
for those who already own a MiniX.
Hopefully I’m getting my hands on one of these pretty soon.
Here’s some pictures.
Picture source: http://mysku.ru/blog/others/8723.html
and running on a small tv: