Something like this? https://www.monoprice.com/products/product.asp?c_id=101&... Plug your devices into a USB hub, then plug the hub into this. Then you can plug this device into both computers and switch between them with a single physical switch.

> They are no Model M

These guys own the rights to make the Model M: http://pckeyboard.com/

And the original moulds, as I understand.

Synergy is good...if you can get it to reliably work with your setup.

I came across this keyboard/mouse sharing software the other day and have yet to try it out but it looks much more promising than synergy and claims there is zero configuration. (works on windows and mac)

http://www.keyboard-and-mouse-sharing.com/

Have you tried Synergy? http://synergy-foss.org/

Synergy is quite good if you can make it work reliably with your setup. When I used it with my Mac as the server and my PC as the client, I ran into a bunch of issues such as modifier keys getting (virtually) stuck. Then I switched it around and made my PC the server and my Mac the client and a different set of problems arose. Luckily, there is an active discussion group and it's open-source, so if you were really keen on making it work, you could.