the only 2 commercially available products i'm familar with that will work on both current console systems and the pc are the x-arcade and the quasimoto but the quasimoto is 2 player only and if i remember correctly the quasimoto is not sold only as a controller only as a complete cab (here's a pic of the quasimoto controller, would have been cool if they sold it separately because it actually comes with both digital and analog controls)

are you sure you really need all those controls? what do you need 2 trackballs for? it is gonna be seriously cluttered or a massively huge frankenpannel.
I tried to cheap out on the trackball and get a desktop trackball and make my own mounting bracket but it didn't work out too well. went with the happ trackball and mounting bracket which is the way I should have gone all along (the x-arcade trackball wasn't out so I don't know if it is any good but I read its pretty good)
if ya have any specific questions i'll do the best I can to answer them but as for a tutorial there isn't much to the build. I used the x-arcade so the wiring was already done. I just took it apart and cut and added wire where ever I needed extra length to reach a mounted pieces. One of the hardest things to do was probably take the damn x-arcade apart because the nuts that hold the controllers in place are "glued" in with lock-tight which can be scraped off but it takes awhile but was well worth it because it allowed me to add a trackball and give me more room for multiple people around the arcade.
A word of advice, when making the control pannel make sure to do a test piece or two first to make sure you get the spacing of the holes right and feeling.
I'm not sure exactly how you would go about adding extra buttons for pause tab and enter, i've been thinking about that myself. the only thing I can think of (besides adding an extra keyboard encoder which I'm not even sure you can have "3" keyboards attached to one PC, could be wrong though) is to map the unused keys on player 4 controller to those buttons since most 4 player arade games only use 2-4 buttons anyways and you'll have 8 plus you could add those buttons to the top of the control pannel by just splitting the line and running the cable to dedicated buttons at the top of the control pannel and also put the buttons at the same place as the rest of the player 4 buttons so you have them there for console games that may need them.
i havn't tried it so i'm just brainstorming on the last idea and this one but I wonder if there is a software program out there that will allow someone to map 2 button presses to act as a single different button press (such as pushing up and the start button, i.e. 8 + 1 and the software tells the computer that you are actually pressing the esc key) then the extra buttons would not be nessessary
I havn't gotten too far into playing with the controller much with the PC. I've got it primarily setup to do so but have just used the keyboard i've got built in under the controller for those keys. I've been primarily playing console games esp tekken 5 that is the greatest arcade game