This is just an idea that arose in IRC (the conversation included nikky and Luxen, in response to an unusual solution to a predicament held by Pieman).
The idea is to port TiLP to an Android app.
I do not have any work done towards this. I do not have a proof-of-concept. I currently do not have the skills to start this, let alone complete it. I'm the one posting the topic, but I do not feel that this is my project at all.
Useful info:
http://lpg.ticalc.org/prj_tilp/architecture.html
https://en.wikipedia.org/wiki/Android_operating_system#Applications

I've thought about this before. It could work with the headphone jack.

Wait. Like calculator to headphone? And vice versa?

I wanna see THAT cable...

I hadn't thought about using the headphone jack. I was only thinking about USB with an OTG adapter (like this)

Here's a 3.5mm to 2.5mm adapter:



Now it will be up to the phone to try to burst data at the correct rate, by simulating a Graph Link. (It's really just serial over 2.5mm.)

Does android have that capability exposed? receiving and sending stuff through the audio port like that?

I was doing some searching and found a post on stack overflow discussing a very similar topic, you can find the link here
http://stackoverflow.com/questions/7931592/how-to-read-send-data-using-the-android-devices-3-5mm-headset-jack

Have you seen mobileTunes 3.0? Its pretty cool, use it a lot