Reduce size of compiled binary

Hey /prog/, I'm making a remote control tool that works over Tor  because reasons.
But Tor itself weights 3Mio and my final executable is over 1Mio upx'd.
I'm compiling in plain C with Visual'12, have activated all the size optimisation but it's not enough. The client must be able to transfer itself over the network very fast and fit even on small embeded systems.

So do you know of any methods to reduce size further, or any packer better than UPX ? I don't care if it makes my code really slow, but size is critical.

>>17
I'm kindof doing the same thing, but I need less functionalities, for example I don't want hidden services on the clients. Onioncat depends on Tor, so it's bigger than what I already have.
I'm just running a custom Tor implementation in a thread and sending data through the SOCKS proxy, I don't really need this.
Thanks for the suggestion anyway.