OK to connect one digital pin to another?

My scoreboard project uses some mechanical switches for the user to adjust the score. I want to connect the switches as one bundle to the arduino board through a RJ45 plug and jack. The problem is, the breakout board for the jack puts 8 pins all in a row. I need to send +5v and ground to the switches. I can probably connect a ground easily enough from the battery, but for the +5, I was hoping to send it up that same bundle. The only way I can think of doing it right now would be to to set one of the digital pins to output high and leave it that way. I can send that up to the switches and as the user manipulates the switches, it would effectively send that +5 back down to a different pin. Therefore I would have two digital pins connected together when the switch is pressed.

I know the arduino has a +5 v pin that I could normally use, but my breakout board for my RJ45 jack will sit on top of 8 digital pins. I guess I could cut one of the pins and route the +5 over in its place, which wouldn't be awful, but I was wondering if there was a better way.

As long as the current demands are low, as they are when powering switches, you can use a digital pin as the power source.

The pins default to inputs, which means they are high impedance and draw little current.

If you connect two pins together and set ONE of them as an output, no problem.

A problem occurs if you make a mistake and set BOTH of them as outputs, AND set one output HIGH and the other output LOW. This can cause a lot of current to flow, and can possibly damage your Arduino. Be careful!

What you are doing is not so unusual and could work. A common way of hooking up an Arduino input pin to a button or switch could have the same disastrous effect if the input pin were accidentally set up for output. This is usually not a problem.

Using input pullup is a kind of double dummy protection. Because you have to make two software mistakes to create excessive current on the pin when the switch is closed:
1- set the input to output
2- set the input high
That's because the default is input, and low.

With input pull down, you only need to do #1 to create a fault. Are your switches pull up or pull down? Is the 5V for the switches, or for other circuitry? If it's only for the switches, you could set one of the pins to a low and use it as a ground for switches wired for input pullup. I'm confused about your statement about being able to connect a ground from the battery. Do you mean externally to the Cat cable? If so, can't you just do the same thing with 5V?

Can we see an updated schematic?

If they are just simple switches then you should only need one ground plus the individual switch wires. Use the Arduino's internal pull-ups.

Other than that, your scheme seems sensible.

MorganS:
If they are just simple switches then you should only need one ground plus the individual switch wires. Use the Arduino's internal pull-ups.

Other than that, your scheme seems sensible.

If the wires are very long, don't use internal pullups. The resistance is too high. You will get much better protection from noise and compensate better for capacitance in the cable with low value resistors, for example 1K ohms.