VNC with reduced color depth

[Homer]

Kubuntu 10.04

I want to establish a connection with VNC to :0 using a reduced color
depth.  My connections will be via modems, so I'm trying to speed
things up as much as possible.  The screen resolution of the remote
machines is set to 800x600 and I'd like my VNC connection to be at a
color depth of 8 or 16.  I don't want to set the color depth on the
remote machines that low as I sometimes sit in front of them.  Closest
I've found so far is tightvnc, but that doesn't allow connections to
:0.