This is a longer version of the 5 block wide piston bridge I did before. It turned out that extending and organizing the redstone wasn't as easy as I thought, but I got it down all with internal furnishings and color coding.
This version is covered with bedrock but if you guys want a version that only has the redstone like my previous one, please comment.
There are 2 blocks next to the lever that are removed which can be covered up. I just removed them so that you could get inside without breaking something.
I can also do a tutorial if anyone wants, or you can just figure it out by studying the redstone =D.

Additional Notes

This doesn't come with the lava.
Be careful when spawning lava because when I used worldedit just to test it out, I replaced the air with lava, but there was an air block right under the block next to the lever which destroyed part of my wiring and I had to redo it.
I used mossy cobblestone to make the bridge, but that can be replaced with anything you want.
Remember to select "copy air" when using the schematic to put this underground.