Being frustrated with launch delays recently, I was wondering about the effectiveness of keeping wallets secret via a password or waiting to release it, and how ineffective that's proven.

I was wondering if it is technically reasonable to provide a wallet immediately, with the hash (exact) of the genesis block (or an ECDSA pubkey that must sign the genesis block), so the actual mining operations cannot start until after that block is released. Obviously, a bunch of users could modify the wallet of FooCoin to accept a different genesis block (released earlier), though then one can't really call that coin FooCoin.

Can someone clarify if this is doable, or why not?