Personally, If I interfaced with potentially dirty signals I would use an optoisolator or optocoupler in my interface design, those ICs are cheaper to replace than a Pandora board. On my Raspberry Pi I don't care to do this because it's a $35 board that if I accidentally blow out it's not the end of the world.
For me it is not only that, but doing anything like this would only be truly meaningful if there was a really solid way to also attach whatever you come up with into the unit while moving it. That means both a solid external connector that would look pretty alien to any regular consumer and/or a rail or tiny bolts or whatever that also affect visual appearance negatively to the average consumer.
I think people interested in something like the Pi and people interested in something like the Pandora are, at the end of the day, mostly pretty disjoint groups of people with only a few hackers at the intersection. I could be wrong, but that is my impression now that I've spent some time on these forums. Take away the people who do not do hardware, only software and you end up with, relatively speaking, just a couple of customers. Take away those who think like you and I do: I wouldn't risk it even if it could be done when there's cheaper alternatives to mess with... and in the end you end up with how many dirty rich individual hardcore hackers?-)
In addition there is simply too little room inside the Pandora to put that much
into it comfortably and "solidly"? Getting wires into the unit would require drilling holes which will affect the case (and amounts of pocket lint you need to clean up ;-) in the long term. The PCB has lots of connection oriented pads as it is already, but they are fairly useless if you end up with a half closed case and a bunch of dangling wires. You won't ever carry the unit anywhere when it's like an octopus. And thus you end up using a cheapo Pi or something like that in your projects instead... even if you were that dirty rich hacker...?
Finally, I have to say that I cannot readily see what you would want to attach to the Pandora that could not be attached on a as needed basis via USB. Since you can compile your own kernel you can get a good portion of available usb gadgets up and running with no/minimal effort (at least compared to writing your own drivers).
But having said all this:
I guess for that very small minority of people who insist on messing with the Pandora it could be useful to have an external connector without any connects to the PCB, just unconnected pads for all contacts.
That should be something very common, easily sourceable like a HDMI connector (it is easy to source: just buy your regular HDMI cable and use that trusty old Leatherman --> you got your connector and some wires already soldered into it as a bonus).
But I emphasize: It would be totally unconnected to anything. Unlike the current add-on/TV-out port.
You would then make a wire tangle crisscrossing from whatever pads you want to use to that connector and start working outside the box.
Right now, however, I'm starting to see even that as waste of PCB and money for a redundant HDMI connector for the reasons above. Also, one problem with something like a HDMI connector is that people assume it is HDMI if it looks like HDMI. And anything not looking like something familiar is not easily sourceable
.
