I just got a second and third seaboard block, and have been very excited to have a 72-note mini-seaboard.
But when I hooked them together I had all sorts of problems. After some reading on the topic, I learned that each seaboard needs to have it's own range of midi channels. That is frustrating, as it limits the polyphony of each block to 5.
True polyphony for multiple seaboard blocks would be a big plus for me. It's what I expected when I bought them.
Also, the present midi-channel-sharing situation seems like a good candidate for an faq. The only mention I found of the issue was on the Juce developers forum.
I'm hoping that's just because you are expecting to fix it soon! It's certainly not in keeping with the easy magnetic attachment-detachment. (Just attach another block.... oh, and also reset all your midi channel ranges!)