I have uploaded the latest batch of updates for -current, which include support for the Banana Pi.
I have written an installation document
that describes how to install on to a 2.5" SATA drive. diffs are welcome to include installation to other targets.
The upstream support for the Banana Pi are currently limited to using it as a 'headless' device, but the Linux SUNXI team have a published plan
to upstream other support throughout 2015.