Limit Switches with LED's

[Jonathan]

Edit: I'm not explaining that very well am I?

No, perfectly well.

I put this diagram in the previous post, but immediately deleted it as I realised the problem you mentioned:

If V=5V, then when one switch is pressed the voltage at the node the breakout board is connected to will be the forward voltage of the LED, so about 2.1V, plus the voltage of the resistor. As you say that's probably acceptable with just one switch pressed, but still more susceptible to interference and probably not going to work with more.
We can fix this by increasing V, to say 24V, and connecting the breakout board via an op-amp used as a comparator. Set the threshold of the comparator to be just under the voltage present when one switch is pressed, then any number of switches are pressed the comparator output will switch. I guess that does loose the simplicity...I'd do it your way, except I don't really see the point of adding LEDs!