Just a thought but if you need lots of inputs/outputs then why not put 2 bob's in like this one - http://www.diycnc.co.uk/html/pcpps.html

You will have to put a second parallel port card in your pc anyway to drive the IO6 so it will end up working very similar. The two bob's will be on separate parallel ports so you can set the inputs and outputs up separately in mach3. Never tried it though!

Another option is to use just 1 bob for the main inputs/outputs and also a standard parallel port connector which you can solder the wires straight to the back for any additional input outputs you need, never had the need to do this either but I know a man that has!

Oh, you might need one of these to make driving your spindle a little easier... - http://www.diycnc.co.uk/html/spindle_2.html