Alright, I'll try my best to address everything from the new responses.
About the controller question; sometimes I get anal about stuff, I know it might not make sense to other people, but it was a thought I had. I didn't want a ugly ass, hacked into NES pad inside the cabinet, because much like my computer, I am planning on keeping it as tidy as possible on the inside.
When I first thought of the NES controllers, I noticed they have a lot of pins on the end of the connector. I had briefly thought that maybe each pin on the connector was supposed to represent a button (please keep in mind I am a electrical newbie), which I quickly realized if that was the case, there wasn't enough pins. After looking at the diagrams for the NES controllers I realized each pin had a purpose but not the ones I had thought. I had wanted to be able to just splice the arcade controls into the NES controller cable and that be it, I now know that's not a possibility.
I know about the logic board, there is no way I am even bothering with that. I am starting this project because it seems the simplest for me and I want to take baby steps, like I said before, I am brand new at all of this and it's a little intimidating.
I had thought about using the computer for just NES emulation, but then I would have wanted it all set up so you didn't see Windows and it had a nice front end and all this other stuff. When I looked online, I couldn't find a NES Emulator Front End. Does MAME run other roms then just arcade games? If that was the case, then I might reconsider using MAME just to run NES games for my NES cabinet.
I also didn't want to dick around with a I-Pac just yet. I am sure it's really easy, but so is soldering some wires to a NES controller. After doing some math, I'd end up saving some money using a NES VS a computer (not taking the PowerPak into account of course) .
I am aware of the NES advantage controller, but I just feel like it wouldn't look as good. I had thought about trying to think of a way of just incorporated the NES advantage into the cabinet so it looked like normal arcade controls. I don't know how that'd work though. If someone has any insight on this though, please feel free to comment. With that being said, I have been looking for arcade buttons that look or mimic the start and select buttons (in shape and color) and have had no luck. I have also been looking for buttons with printed letters on them (A and B) but haven't seen any yet, if anyone knows something I don't, please let me know.
I do not want to get a reproduction NES system because a lot of them suffer from incorrect colors, sounds and some incompatibility issues with games. I can buy a old NES front loader for $20.00 and repair the 72-pin connector for free.
As for the cabinet, right now I got a feeling I am going to be building it. I honestly didn't really want to and I have been scouring my local area and the internet for cabinets I might be able to buy or pick up, but they are either too far out of my way or way too expensive. I am trying to do this as cheap as possible and I don't want to drop $300.00+ on one of those damn arcade cabinet kits so many sites sell. One guy 4 hours away from me had a TMNT 4-Player cabinet he'd sell me for $30.00 with everything intact, but I just couldn't find a chance to go out there.