I just can speak for the 2000classic but it should be the same for the 3000.
The 16Level function is a AKAI specific way to program/control settings like tune or velocity. Its not included in the MIDI standard protocol (well not in this way)..
What AKAI did with the 16level button was switching the pads from sending the standard MIDI messages Note On(+Notenumber of the pad/key) & Velocity to sending a NOTE ON (but with a FIXED note number -> the pad you've choosen) + 16 different velocity values (16level velocity) or 16 different pitch bend values (for 16level tune). These pitch bend values are the same as if you turn the pitchbend wheel on your keyboard.
There is a workaround for a keyboard to perform in such way but you'll have to use a PC and a software like PureData
http://puredata.info/ to transform the standard messages from your keyboard to the messages you want. This way each key of the keyboard would send the same notenumber but each key will also send a fixed assignable value of velocity or a pitchbend message.
Depending on your keyboard this wont be limited to 16level. You can have 49level or 61level or .....
peace
