So I don't think this is something anybody supports:
arc> (= grail (otable a "up" b "down"))
arc> grail.0
"up"
Ordered associative containers merely have a well-defined order for iterating over. And the order has nothing to do with the order in which elements were inserted.
So what you're asking for is interesting and plausible, but I don't think "ordered tables" is quite the precise label for it.