To my knowledge - No, this currently does not work with the Touchpad... Unless I am misunderstanding what that device is... What may work, since the touchpad DOES support USB host, is a USB display adapter.http://www.amazon.co...r/dp/B002GHBW4S
This is an example of a USB display adapter, its basically a very weak USB based graphics card. They usually only support 2D acceleration, and are 100% plug and play. I'm not sure if these will work with the limited linux environment Android is run on, but it may well be worth a shot, if someone already has one and the USB OTG cable, they could test it easily, though I'm not sure if Android has multi-display functionality built in correctly. Someone with more insight on how the Linux environment Android runs on and the inner workings of the operating system could probably answer the question without needing the hardware to check.
Interesting, after a little more research into this field of things, DisplayLink has an Android Driver available... DisplayLink is a USB->Display technology, and I believe there are hardware adapters for the DisplayLink technology (Basically, the driver feeds compressed video frames over a standard USB link to a basic framebuffer device, which then decompresses and decodes the frames and sends them through a standard display interface - VGA/DVI/HDMI) Some screens supposedly have their technology built in and can be connected via USB 2.0 directly.
The last line on this page shows that the driver is available for Android:http://www.displayli...ed/software.php
And here are a bunch of DisplayLink adapters:http://www.displayli...m/shop/adapters
Here is a basic functionality proof of concept app for root users:https://market.andro...mFtZWJ1ZmZlciJd
This app directly sends a picture (so not video, and not a second display, as well as no audio - so not what most people would want) To an attached framebuffer device (I.E. DisplayLink) for display on a screen. I'm not sure, but it may be feasible to add this functionality into CM9 source code, though it would likely take a bit of work - though it would be well worth it since a large number of devices are starting to support USB Host mode functionality - and there are still many devices NOT including HDMI output stock.
Scratch that last bit, watching the video the guy has provided - it looks like he is able to start, and run a FULL X11 instance on that USB DisplayLink adapter. Pretty impressive... and he did all that on a Nexus One... I think its time I start learning how to hack away at the Android source... This is the kind of thing worth contributing to a project like CM9, it would be viable for all host mode enabled devices...
Edited by Xaero252, 05 March 2012 - 04:33 PM.