IMHO,
If you are OK with 2 keyboards, use a great quality 88 note graded hammer action MIDI controller on the lower (under an arranger of your choice). There are some lighter ones out there. A while ago I had a Kurzweil K2600X under my T2 (then the PA2). But currently I don't Gig out so I didn't have to move all that around.

It's nice because you then have a upper that's synth action and a full 88 piano keyboard on the bottem (at the correct height also)My setup was so close that it was exactly like having a 2 manual organ.

Diki, yep I agree...I would rather use a footswich (or one of the 2 DNC switches on my PA2) to do the slide. Not velocity.
PA500 or PA588 doesn't currently support DNC, Not having one however there may be another way to do the slide besides velocity.

Lee S.