That is a great idea. I can't believe I didn't suggest it, because I'm doing something very similar right now!
In my case, it was inadvertent due to some mixing problems and the ensuing corrective action that led to having a half gallon of 1.061 wort and some extra yeast starter. Fortunately, I didn't throw them out in frustration at 2:30 am while fixing the real batch, so the next morning I pitched the yeast... It's lagering now, so we'll have 4-5 bottles of a sorta makeshift partigyle bock.