I don't know how small and how light you need but I recently got a Juno-DS that is lighter than any other board I've owned, 61 keys and has 2 1/4" outs, USB that can be assigned to computer or MIDI at will, MIDI (old style) as well, and some other connections (mic in for vocoder etc).

Like I said it's pretty light and has a ton of sounds.
https://www.youtube.com/watch?v=owWzJVh2ink


Make your sound your own!
.. I do not work here, but the benefits are still awesome