What do you guys consider the best way to have fills triggered on your arrangers?

I'm especially talking about the most efficient way, while you are playing, to select from at least four variations and maybe 6 or more fills. I know some keyboards give you separate buttons for the variation AND fills, but to my mind it always seems too many button pushes. Some arrangers allow you to just select the variation, and a predetermined fill will play to bring it in, but this way you lose the choice of fill........ I'm also especially interested in 'hands free' choices (I play a lot of LH Bass)

So, everybody, what do you prefer, what systems have you seen on other arrangers that you thought, 'hey, that's a good idea'? Anybody got some good ideas for how arranger manufacturers might improve their systems?

I'd like to hear your thoughts........