I don't see any reason that it can't be used with a verb, as long as the verb is followed by の:
Verb + の + ならいざ知らず
If you do a search on Google for ”するのならいざ知らず” you'll find a very small number of hits, so it doesn't seem to be very common. However, one of the hits is an article on Asahi.com so it seems likely to be proper grammar.
The specific sentence is this:
As there was still some doubt about this I'd like to point out that the phrase 。。。いざ知らず means something like the below: (reference)
So I think the important thing here is いざ知らず, and there isn't necessarily set word(s) that must fall before it.
To give a simpler example of using a verb with this, consider this phrase:
This would translate roughly to "I don't know whether you can do that type of thing..."
I don't think there is too much limit on what can go before いざ知らず, though it must be grammatically sound. For example, "するいざ知らず" would be awkward and improper grammar. But as long as there is a の after the verb I think it is valid.