Is there a way to maintain a continually updated copy of blockchain without running a wallet? This question is in response to being stupid, as I just tried to spend from my B-Qt wallet before it was finished syncing (power outage fun yesterday). Was scary when it froze after hitting send, had to force quit the app and relaunch. Hopefully nothing was actually sent and I can redo the transaction. The bitpay invoice did expire, so I'm hoping for the best.

But it got me to thinking if there was a way to keep an updated copy of the blockchain without actually having to keep my Bitcoin-Qt wallet running. Because security? Presumably I'd be able to point the Qt client at this updated blockchain in the event it hasn't been synced for any amount of time, and it would negate the need to get caught up.

Is anything like this possible or already in existence?

I know I could use a sync-free online wallet but I do not want to store coins anywhere but locally. The point being to have a non-wallet blockchain sync but only activate the wallet part when I want to spend.
You could keep two wallets, an 'updater' wallet and a 'secure' wallet, and use the same blockchain with both using the following instructions:

Separate wallets sharing the same blockchain?

The updater wallet would run most of the time, and then you would switch to the secure wallet when needed. Heed the advice about not running two wallets on the same blockchain at the same time.