Chirp has support for automatic repeater offsets. I haven't looked into it in detail, but I assume this is for the North American band plan?

Yeah.

Australian Amateurs have their own band plan that's based off ITU allocations and tailored for the region: http://www.wia.org.au/members/bandplans/data/documents/Australian%20Band%20P...

Any thoughts on the acceptability of supporting selection of band plan? They could be bundled as text files that include repeater offsets, suggested modes, power limits etc? The automatic repeater offsets option would become an automatic band settings option. Devices that support band limits could also import them as band limits (eg. bug #651http://chirp.danplanet.com/issues/651 ).

Fine with me, although I'm not sure we need to go so far as an external parseable file. Could we just have a regions.py file (perhaps in chirpui/) that would be a dict of dicts to expose regional differences?

Something like:

regions = { 'us': { 'name': 'United States', 'auto_repeater_offsets: (the data structure from common), 'amateur bands': [(1800000, 2000000), ... ], }, 'au': { 'name': 'Australia', ....

?