I asked that specific question to the Strand guys at LDI. I was told that there are not going to be any sort of wing panels or other add on attachments available. Which I found really dumb because the software is clearly capable of handling it... why not sell physical upgrades to the system. Maybe they will see the light.
It's also really interesting to note that there is no difference in software between the lowest priced Palette at less than $10k and the highest priced Light Palette at around $35k. All you get for your $25,000 is encoders, a few extra buttons (maybe a lot if you get the VL), a faster processor, and they unlock the software to allow more circuits and attributes. Don't tell me it costs $20,000 for a faster processor and some encoder wheels.
ETC on the other hand took the opposite approach with the $25,000 Congo. They knocked the price down ten grand, shrunk the case but didn't change the functionality... the only difference is a few less banks of buttons and sliders, and there's no room for the handy LCD screens on the console to tell you what you have loaded in those buttons and sliders. Everything else is the same. You still have all the programmable buttons and faders, just less of them. That's really cool because it brings a very powerful system down into the price range of a lot of smaller theaters.
Remember, "EOS Jr." (or whatever they call it) is coming next year. The ETC rep at LDI told me it would have all the functionality of EOS but in a smaller package for around $15,000. That's going to be one killer product.