sysex output is already possible, I replied to your PM explaining how...
generally anyone wanting to do this should look at my code for the Ableton Push
you will see call to MidiSendSysEx
you should also be aware that the size of the sysex message is limited to the size of the ring buffer, in practice this will means 192 bytes for the sysex BUT if you have any other midi messages 'in flight' these also will take up space at 4 bytes per midi message (FIXED size ... thats the way USB midi works!)
if you get warning about ring buffers overflow.... then you know your message is either too long, or your sending them too fast.
(you will notice in the Push code, I'm quite careful to minimise the amount of data sent, and also ensure that it is sent out at a limited frequency.... I don't just push the display constantly or triggered off 'user input')
This is all subject to change in a future release