Use a little windows utility called "sortinfo".
http://www.zophar.net/utilities/arcadeaud.htmlJust run the command "mame.exe -listinfo > listinfo.txt" from the mame directory. Then run sortinfo, and import the listinfo.txt file. This program will display sortable lists of all the game information including control type, and monitor orientation.
How to get a list of controls for vertical monitor games:
1) Click the Video tab.
2) Click the Orientation heading to sort by monitor orientation
3) Click the 1st horizontal game
4) Scroll down to the last horizontal game
5) Press the shift key & click the last horizontal game to highlight all horizontal games
6) Press delete key to get them out of your way
Now you have a list of just the vertical games.
1) Click Input tab
2) Click the Control tab to sort by control type
Now you will see the whole list of vertical games organized by control type!
1. Do any vertical games in MAME use an 8 way joystick? Or just 4 way and 2 way?
More than half of the games use an 8-way joystick. Several use a trackball, analog joysticks, spinners, steering wheels, rotating joysticks (ikari warriors style joysticks), (etc.).
2. Do any of the vertical games need a lot of processor speed? Could I get away with like a pentium 1 133mhz or pentium pro 180mhz? Or would I need at least 300mhz?
I don't know what speed you would need... On a quick glance, Toobin' might be one to use as a test - I think it needs a faster computer than most. I'm pretty sure that I can run pretty much all of those games perfectly with a pIII 500 mhz.
3. What is the most amount of buttons used on any vertical game supported in MAME?
Again, I'm looking at listinfo. It looks like the vast majority of the vertical games use 3 buttons or fewer... Some use 4 or more... I would test out the 4+ button games to see if you really need the extra buttons. You might be able to get away with mapping the start button as button 4 in most cases.