Look for an Aria Pro II bass from the early 80s (made by Matsumoku), specifically the [Invalid or Expired Link Removed] and [Invalid or Expired Link Removed] models, which are all medium scale and very good quality.
For instance, here's one in the TB classifieds: For Sale - Aria Pro II TSB-400 Thor Sound - MEDIUM SCALE!
Also, the new one from Ibanez: New Ibanez SRMD200
Aria was my first thought.
This is medium scale if you have nostalgia for the 80's -