Perl multithreaded Amazon Glacier client
It's written in Perl for POSIX systems (there are reports of successful use under Linux, BSD, MacOSX, Solaris).
It does have extensive testsuite, minimum dependencies, "full" unicode support (well, of course it's not full. there is probably no single application with full support),
multithreading implemented using fork(). HTTP(S) using LWP::UserAgent with workarounds for existing issues. Total SLOC is over 20k, more than 1000 commits.
Full list of features: here