Thank you a lot!

But looking at this matrix: http://www.gnu.org/licenses/gpl-faq.html#AllCompatibility
…it seems okay to link LGPL-2 code to both LGPL-3 and GPL-3 code, so I don’t really see any advantage of having the additional LGPL-3 license.

Looking more closely though, LGPL-2 seems to have a GPL-2+ clause, not a GPL-2 clause:

You may opt to apply the terms of the ordinary GNU General Public License instead of this License to a given copy of the Library. To do this, you must alter all the notices that refer to this License, so that they refer to the ordinary GNU General Public License, version 2, instead of to this License. (If a newer version than version 2 of the ordinary GNU General Public License has appeared, then you can specify that version instead if you wish.) Do not make any other change in these notices.

…I’m not seeing the same clause in LGPL-3 though, so maybe that’s a better license then?

There is of course nothing preventing somebody else to help out with this too on his/her own initiative. So if you or somebody else feel that they can contribute in this area I would be very interested to get in contact with that person!

It sounds like you were not strictly opposed to LGPL-3, just worried that you don’t know what LGPL-4 might bring. I’d suggest that used “LGPL-2 or LGPL-3″ as you licence. i.e. people can reuse it under the terms of one, or the other, whichever suits them best. This has the advantage that if one day someone wants to include some LGPL-3 compatible code in the future they will not be prevented. (there have been some awkward cases of GPL-2 programs having problems if a library they uses switches to GPL-3 only).