I would go with the new mspacman 4 way joystick myself. best new 4way imho.
look at
www.therealbobroberts.com... but a good vertical 4way only classic would be great!
what size cab are you building? I'm curious if you should consider going with a hotswap control panel... so if you want to add an 8way (or a button only control panel for asteroids ect)... you can... easy cheap way to do it is buy some 3 foot 25pin male-female cables (about 3 bucks each) and you cut them in 1/2... use half on the control panel... 1/2 to the encoder... and you can now unplug everything and later buy some 25 pin m/m... cut in 1/2 and you can make 2 more control panels..
I love ipacs... I also own a few keywiz's... also great... cheaper... only issue is you can't configure them, and have them keep the configuration on a reboot.... I always thought it was very important.... but it ends up that I don't need it after doing the right cabling.
make sure you get quick disconnects for cabling. very worth it in the long run.
Buy good wire... make sure its NOT solid core... makes cabling a pain... and any small move and the connections break... (the 25pin serial cables mention above works... but they are thin.
All I can think of at the moment...
good luck