To be hep on X

[Suzanne Evans Wagner]

I recently heard this expression, which a Google search reveals to be
marginal but definitely present in colloquial writing, especially blogs and
discussion groups.

It most frequently appears to be synonymous with "keen" and collocates, like
"keen" with "not too" eg.

"...I’m not too hep on the idea of getting into a long conversation
 with my mom about the surgery while I’m there..." (www.infinitepink.com/blog)

But it can also be used (like "hip") to mean "well informed, up-to-date" as in

"Thought I was hep on all the jargon used in The ABERREE, but what in hell is
mysticology?" (www.aberree.com)

Some of the tokens I found suggest it might also be used to mean "worked up
about [a contentious issue]", "obsessed with" or just "enthusiastic about".
There's also a "to be hep up on X" variant.

Does anyone on this list recognize this phrase and know if a) anyone has yet
written about it in the dialect literature and b) if it's associated with a
particular region of the US?

Suzanne Evans Wagner
University of Pennsylvania