XSSN / XS-SN
x-session is my weapon of choice when it comes to mobile vj setup. it offers 16 knobs and one long-throw crossfader. It may not feel expensive but unless you're a hard-core scratcher, it should last.
The crossfader is quite cool, it's long but very light and you can send rapid control signals using very little strength. Abusing it for the whole night straight would probably still end in some serious hand injury but it's better than using V4's T-bar to a point that I kept their CCs the same, just in case. With long enough MIDI cable you can control the mixer being good few meters away from it.
Unlike it's younger brother, X-Session PRO, this one has External Midi IN and OUT on dedicated DIN-5 connectors, and power switch as a bonus. X-session had a second codename of uc-17, which was released quickly after uc-16, which was a close relative to loved by some and hated by others 'UC-33' from Evolution, now owned by M-Audio, now owned by AVID.
At some point. I used to split 9V power from my RM1X monstrous power supply and feed a bit of that power to X-Session (UC-17), so it could compensate for yamaha's lack of CC-sending knobs, leaving audio path free of computers and allowing for much greater control of my sampler. I used to then sometimes take that MIDI from the other end of the sampler using THROUGH, and feed it to the computer through USB THEN.
I'ts only a shame that the keypad is useless to a point that it's best not to touch it - unless you have the manual somewhere. That's a serious fail of this device, which has 20 rubber buttons on the surface, and once you program it, the only useful thing you can do with them requires pressing two at the same time, to toggle between MIDI-OUT mapping to either messages generated by the unit itself or sent by your host. State of this switch is indicated by a small 'usb->midi' indicator on the LCD. Forget about using them as pads.