Thanks.
Unless this solution provides real benefits for users, I think having a single working .deb for users is better and less confusing for them (so they won't ask "which one should I use?!"). And creating a proper .deb which doesn't cause MALF on anyone's N9 needs some time which I'd prefer to spend elsewhere if I found it!

And for more experienced users, testing my solution should be fairly easy: all it needs is a hex editor (or a sed like utility for binary files) to replace UCS-2 with UTF16 in libsms, copying it in /usr/lib (preferably after backing up the original one!), and update refhashlist (needs 'real' root access, e.g. using opensudo).