I've been using the SIP stack library reSIProcate
http://www.resiprocate.org/ a lot this week, and in general it's a very nice real-world example of RAII and exception error-handling in C++. It has a bit of magic in its reliance on preprocessor macros for defining SIP header-specific methods from a single macro 'template' - but this seems to be the only way to use proper C++ typing to model the different parsed headers and keep things maintainable (although I'm aware people have tried to use mixins and roles in C++, i have no idea how well that works in practice).
http://estacado.net/resip-dox/stack/classresip_1_1 SipMessage.html is an example of the doxygen for the fundamental class which describes a SIP message - browsing around the doxygen should given an idea of the rather nice RAII idiom they use, as well as the interesting usage of macros...
Picking a file entirely at random,
http://svn.resiprocate.org/rep/resiprocate/main/re sip/stack/test/testUri.cxx is both a good example of RAII being used (from the user's perspective), and a fairly good example of a comprehensive C++ unit test (without any faffing around with a unit test framework). The class being tested is their class for expressing SIP URIs (surprise surprise).