Folks working with 802.3 (Ethernet) hardware (10/100/1000) can rejoice, as I've now integrated PSARC 2009/319, which provides a common MII and GMII layer for Ethernet device drivers. The first batch of drivers (iprb, dmfe, and afe) have been converted. This brings support for SunVTS netlbtest, dladm based link management, and even (for some devices) 802.3 flow control (aka Pause Frames) to these drivers.
I'll encourage folks working with other drivers to update their drivers to support the new framework. On average it cuts about 1500 lines from most drivers, and generally improves device functionality.
And yes, it works with Ethernet, even 1000Base-X should work (although only 1000Base-T has been tested.)
Any device that supports Clause 22 of 802.3 should work. Clause 45 (typically 10Gb) is not supported, however.