Behringer, M-aduio, Akai, Novation, Korg, Edirol, they all make Midi keyboards.
You won't be abile to play any audio using a midi keyboard on its own, as they don't deal with any audio, as they only send out messages, such as what note has been pressed and what octave,
if you have it hooked up to your computer (probably these days it will be USB instead of an actual midi port) you will be abile to trigger sounds using FL studio (i have no idea what sibelius is, so i can't say anything like that)
You can also get hardware sound modules, that connect to the keyboard using a standard midi cable.