"Who I conclude"

I have a post on the stimulus bill where I write something like:

(1) "I have listed economists who I conclude would prefer no stimulus bill at all to the stimulus bill that Congress has passed."

That sentence bothers me. Compare it with:

(2) "I have listed economists whom I conclude would prefer no stimulus bill at all to the stimulus bill that Congress has passed."

Which is better? We say "who would prefer", not "whom would prefer". In ordinary language, uneducated people, and perhaps the educated, would say "who I conclude".

On the other hand, I think educated people would say "whom" if they were thinking hard. If "who" is to be in the accusative case, it should be "whom". But "conclude" is not a transitive verb.

Perhaps this is how it should be:

(3) "I have listed economists who, I conclude, would prefer no stimulus bill at all to the stimulus bill that Congress has passed."

But that doesn't sound right to me either. Any ideas?