I would also consider the Keywiz fro groovy game gear but I quickly get confused as to what sort of emulator I should get since they have emulators for all kinds of controls (360 etc).
You mean 49-way joysticks.
So given this configuration (keep in mind I may put a 4 way back onto it and I will have at least 2 buttons on the side for flippers and VP), what emulator should I get? I would prefer screw terminal (non-solder) connectors if at all possible.
Counting inputs and ingnoring the mouse buttons on the trackball and the flipper buttons, it looks like you have 31 inputs required.
You have three options as I see it.
The KeyWiz is 32 inputs and PS/2.
The GGG GP-Wiz is 32 inputs and USB, but looks like a gamepad to the PC, so you need to reconfigure MAME to use Gamepad keys, but that's not a big deal.
Or there's the I-PAC VE, which is also USB.
Either of the GGG products will be about $35 with the screw terminals (which I recommend) or $24 with an IDE header.
The I-PAC VE is $35 with screw terminals.
Your mouse buttons should be covered by whatever interface you use for the trackball.
Your flipper buttons can either share inputs with the action buttons or you could convert the admin buttons to one-click shazaaam! buttons using RandyT's adapters to free up more inputs. That would also go for the four way.
FWIW.
See
http://www.mameworld.net/tigerheli/encoder/shiftkeys.htm for more on the adapters.