Quoted from batcitypinball:
1. Use the extra P3 buttons to switch weapons. Obviously the different weapons ala borderlands would have different attributes, but they would correspond to goals on the table. IE one would score more damage to the bash toy, one would start with jackpot multipliers, etc. Mixed with P3 software, you could even do something crazy like Sniper rifle does huge damage or huge jackpots, but you can't hold the flippers.
I was thinking of something along the same lines. Let's say that you can equip 2-4 guns which are cycled through using two of extra buttons. However, if you are carrying additional guns that you want to equip, you would be required to cradle the ball and then press both of the switch weapon buttons (or another button?) to pause the game and open the menu. From there you would be able to switch out equipped weapons and make other adjustments. Most of the fun in borderlands is finding that perfect weapon combo that just eats through the enemies.