That's one of the good reasons to look for cels from more obscure or not-so-popular shows.  You're more likely to
come across something, unless it's a show that's been around for more than a few years, or was short-lived.

I'm having a hell of a time trying to track down some quality cels from Patlabor TV.  All I seem to find is the
red rent-a-labor version of the Ingram.  Gaaah!  
It's akin to showing up at a liquidation sale about 2 hours after the doors opened--the pickins' are pretty slim...

/me suddenly remembers he borrowed more tapes of Patlabor.
Wai!  Wai!