It sounds like Lenovo will be releasing an upgrade to the Android OS for its ThinkPad Tablet. The release will be coming out in the second quarter of 2012. I'd really like to see an enhancement to the pen-based Notes Mobile app on the ThinkPad Tablet. I really like using the pen to scribble notes during a meeting. It seems much less intrusive than typing on the screen. However, the Notes Mobile app on the ThinkPad Tablet is still very basic and primitive, especially when you compare it to applications like Microsoft Office OneNote for Windows.
I'm still waiting to see if Evernote will be updating its Android app to support pen-based tablets like the Lenovo ThinkPad, the HTC Jetstream, and the Motorola DROID Xyboard 10.1. My prediction is that pen-based input will eventually become a standard input method on all tablets. Apple will eventually release an iPad that will work with an active digitizer stylus pen.
For now, I'm going to continue testing an app called Quill. This $1 app was developed on a ThinkPad Tablet and seems to be much better than the built-in Notes Mobile app. You can export your notes on Quill to Evernote, so this may be the best workaround option for now.