I'm running version 0.3.19 and I cannot find neither getblock nor monitorblock. Are these new methods coming for 0.3.20? Well, if getblock does what I think it does (ie, return all information available about a given block number, including block hash and transactions) then it would of course be an alternative way to implement the "shoot-myself-in-the-foot" client. Everybody can be happy, yay!
They're not in 0.3.20; maybe 0.3.21.
https://github.com/gavinandresen/bitcoin-git/tree/monitorreceived
... is the not-yet-ready-for-prime-time branch they're on.