I vaguely remember reading somewhere that 「～といわず、～といわず」 doesn't come in 否定文, but I came across negative usage of late. Research took me to this site maintained by a native speaking Japanese teacher who claims:
Okay, great. Wait, what's that in your examples?
Literally two lines below, that page uses a 否定文 as an example sentence.
Here's another example I found, in a work of fiction translated by 菊池寛.
So what's with this talk about ～といわず、～といわず not occurring in 否定文?