As far as I know, BSD is not compatible with GPLv3. So I doubt that a Joomla bridge will still be legal.
Actually, BSD is GPL-compatible.http://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenseshttp://en.wikipedia.org/wiki/List_of_FSF_approved_software_licenses
Most GPL-licensed software (i.e. Wordpress, etc) can have extensions/plugins licensed as GPL-compatible licenses, including BSD license.
However, in the Joomla case things may be more complicated. Because according to Joomla,
Can I release an extension under a GPL Compatible license?
Extensions extend and derive from Joomla! and Joomla! is GNU GPL. Therefore extensions cannot be licensed with a less restrictive license.
For more than two years the Joomla! Project has clearly stated that in its view and the views of the legal experts we have consulted extensions are almost always derivative works for Joomla and must therefore be licensed using the GNU GPL.
BSD is a permissive open source license, GPL-compatible. It is obviously less restrictive than GPL itself.
It seems they require
GPL only for extensions, that is, it sounds to me like they do NOT accept a GPL-compatible license.
I will look into this more throughfully though. To my knowledge of past issues as well as other open source projects, however, it is sometimes - like in this case - the choice of the respective software project to accept or disallow extensions licenses in the strictest interpretation of GPL possible - and by that, forbid even GPL-compatible licenses
Please don't take this as anything but initial brainstorming on the future of Joomla integration, now that SMF itself is BSD licensed, though. I appreciate further opinions on the matter.