Bass Rental.
 

For reasons not germane to this post, I've given up on Talkbass. But there's always a downside, and here's mine.

I need to find a relatively inexpensive bass rental in LA for 10 days in May; I've had good luck finding such things on that forum, but it's not worth going back there to ask this question....

Does anyone have an idea of who I could call?

Try http://rentabass.com. There seems to be one for rent in L.A. You could also try contacting Lemur...