I found an ebay seller who sells new SOG L69 leather cases for the PowerLock/PowerAssist for $9.20/each with free shipping. I ordered a case from him and will post the results when I receive it.
If the new case is the same size as my old leather case, I will wet one of the cases and stretch it to fit the larger PowerAssist and use the unstretched case for my PowerLock.
My old case rides a little high above the belt and pokes me in the side, but I don't expect the new case to ride differently.