Notational Client for Android.
I was browsing on the Play Store yesterday, and I came across a great Notational Velocity client for Android, and Holo as well! It is called Notational Acceleration.
I was wary of it, as it seemed to be an imitation app, but I was mildly surprised when I realised when I first opened it up. It turned out as holo, despite the screenshots on the web interface of the Play Store, and it actually seems great. It also has a great tablet app as well, though I have not tested this.