Automatically redirect any incoming BlockChain.info addresses to a new address?

I've been using Blockchain for awhile now, so long, in fact, that I'm not even going to attempt to take a gander at how long I've been signed up, because, I'll probably be off, but, it's at-least a year, if not more.

Anyway, with the recent jump in Bitcoin prices, I no longer feel like I trust a web-wallet with my 1.5BTC (I know it's not a lot, but, still a lot to just 'lose'), so, I want to move it over to an offline wallet (At this time, I've not chosen, but 'Armory' seems very nice due to it's offline-online nature, when using it with two computers). My only issue is, however, I'm registered to lots of sites using the tens of Bitcoin addresses I have active on Blockchain, and, most of the sites actually authenticate you using your Bitcoin address (And not user:pass), so, changing my address would be a huge pain.

My simple question is, is there a way to tell Blockchain to redirect any incoming payments on my already existing Bitcoin addresses to a new Bitcoin address? I'm not trying to be super anonymous, so, all of them can just simply come into one base address, I don't need a unique new address for every old address. I know you can do it using their API, with a brand new Bitcoin address, documented here, but, that's all I could find on the subject.

Obviously, I could also run a script that logs into Blockchain and withdraws my money every 24 hours or so, but, that'd be a pain to write, find a server which can run it securely, and then manage it.

Thanks,
Automatic.

EDIT:- This was obviously me being stupid, I just realized I can take the private keys out of Blockchain and import them into any-old application, so, I guess the question changes now:-
What's the best, open source, simple (So I don't have to spend hours reading through the source), Bitcoin redirector? I just want it to accept the BTC, then send it off to a new address, preferably runnable with very little HDD/CPU/RAM, so, I can throw it on an existing server of mine.

Thanks,
Automatic.