I've not seen anything that does that. Another option may be to use
TwinVNC on the Amiga and any VNC client (e.g. RealVNC free edition) on the windows box. This does bidirectional clipboard sharing as standard, works well.
You just need an Ethernet adapter in the Amiga. Or it may be possible to use a serial network from the Amiga (using Miami) to the PC; depending what software you can find to support this on the PC side.
