Really cool - I've been doing essentially the same thing for some of my apps, but I never got around to covering all the UI components and packaging it up in a library. I don't have time to test it now, but does it come with the Holo versions of Spinners and DatePickers?

Doesn't appear to yet. The author says its still a work in progress, and its great when people contribute.

I wonder if this has any issues across different manufacturer skins.

(Android 4.0 added the requirement for the stock Holo theme to be included on all devices (for developers to use: not as the default) so that apps could be styled more predictably).

I suppose it might, though the goal of the project seems to make all devices look holo and is restyling most components anyway. Giving a base Holo theme for any project on any device, I imagine.

This seems pretty awesome, will try it out. Was under the impression that Theme.Sherlock gave you 'holo everywhere', but maybe this isnt the case..?

It doesn't. I was under that impression as well, but it definitely leaves buttons and text inputs the same. This theme vastly improves ABSherlock.