Green mobile 1.1.1
It seems that's the only theme for mobile devices, apart from the default one. Green and orange shades of colors.
To activate this mobile theme after unzipping it in your themes folder (because AFAIK there is no UI for this yet):
Add $Configuration['Garden']['MobileTheme'] = 'green_mobile'; in your config.php (below the normal Theme for instance); or modify your current value if MobileTheme already exists.
2011-03-05 : v1.1 Search support added
2011-03-06 : v1.1.1 corrected non-display of search box when messages where selected to be displayed in dashboard or all pages.