[Dovecot] Sieve as mail client?

A slightly off topic question, but maybe someone here has seen something like this:

I want a program that operates entirely on the client side of an IMAP server, and implements the sieve filtering language by doing the necessary client side operations to move mail on the IMAP server, expunge mail, etc.

It would also act as a proxy between my real mail client and the IMAP server so I'd never see any mail that hasn't been filtered first.

The benefits are obvious: I could finally get sieve filtering on my stupid corporate exchange mail server :-).