There is a web-page where Adam Taylor lists 10 alternative FPGA development languages: http://www.eetimes.com/document.asp?doc_id=1329857 On some languages the OO-word was used ... I commented that the only thing I have seen so far from these languages is that they are (truly) class based but that I haven't seen any real example. Yet, as I did not study them to their deepest extent, having not enough time and too much other work ...
I already use class-based design for my MyHDL work, see my gist https://gist.github.com/josyb/afd84c9a06fdec77f2fd, but this is not OO as none of these classes have been subclassed.
In stead of doing some real work today (Sat Oct 22nd 2016), I decided to give OO in MyHDL a try. You can see the results in the two next files.