Currently Renoise supports using two midi-in controllers at the same time.
In Windows you can use some third party stuff to try (Chapter “merging MIDI data”):
http://www.renoise.com/indepth/tutorials/a…ng-for-renoise/
On the mac you can do:
http://www.renoise.com/board/index.php?sho…amp;#entry94856
At least for now it is hopefully better than nothing…