I'd try Santana and his choice of one pitcher. Actually, for Johan, make it any one hitter and any one pitcher.
If he insists, give him two pitchers, but keep Cahill for yourself.
How hard is it for your to recoup prospects? In my league, you can't just fill open slots, and so trading them away means the potential for empty minor league spots.
If you can pick up minor league FAs after the deal, then I'd pretty much give him anything he wants, assuming that there are minor league FAs you like.