Are there any LTL to _non_ deterministic Rabin automaton translators?
You can easily translate LTL to non-deterministic Buchi automata, which can be thought of as a simple fragment of Rabin automata (although they are equally expressive).
I don't think any tool would actually output the acceptance condition described as a Rabin condition, but this is very easy to deduce from the Buchi states.

An example of an online tool to do this conversion is:
http://www.lsv.ens-cachan.fr/~gastin/ltl2ba/

But I'm sure there are many others, as the construction is relatively simple.