Please see this post for the more recent Dolphin Browser add-on.
I've just ported my app Tampermonkey for Google Chrome to Android.
Please note that it is still in beta status. Atm Android 2.1 is required
May be you can play a little bit with Tamermonkey and test some Userscripts.
Due to the fact that phones does not have a really fast cpu, you may have to be a little patient.
If there are non working scripts it would be nice if you could test it with Tampermonkey for Google Chrome and Chromium too.
Tampermonkey for Google Chrome and Chromium: