I've been using the same wallet.dat since 2011. I'd like to use HD address generation, but with the current implementation that would mean switching to a new wallet and losing all my transaction history.

Would there be any interest in adding an RPC generatehdseed or some such that would enable HD address generation for old wallets, and switch to a new random HD master key for wallets which already use HD generation? It could optionally regenerate the keypool so that all pooled keys are generated from the new HD seed, but should warn that a new backup is required if the poolkey is regenerated.