There is a lot of anecdotal testimony about figs fruiting at an earlier age, if kept in a pot. Does anyone have any sense that figs in pots ripen earlier than ones which are in ground?

Jon,

I've only had one type of fig in the ground and I now have their offspring in containers.  The containers ripen later than the inground trees.

The trees in containers started producing at a younger age than the parent trees (inground) trees did.

~james

Here in the north east, defenitly my potted figs ripen much earlier than the ones in the ground. The main reason is that they are usually protected and not fully dormant in the winter, the ones in the ground go fully dormant and take longer to break dormancy.
Another theory I have is that the container may be warmer than the ground when the sun rays hit it, therefore they ripen earlier.