egads - that thread is almost 12 months to the day, and I still haven't released the ML changes.
To answer your question, I haven't yet tested directly against the apollo module, I have verified it works OK with the adequation module, and when I last looked at the DSLocalizator, it wasn't working exactly correctly, though some people report getting it to work OK. The problem with the DSLocalizator is that, for me, it did excessive modification to the core, and so will probably fall out of compatibility pretty quick unless it's well supported with each new release of DNN.
I do have a beta running of the ML stuff, and it does most of the things I said in that other thread. Not sure on your timeframe for ML changes but as you have a proper test site perhaps you can have a look at an early beta. The biggest problem for people is that as soon as you turn on ML, all of your existing pages tend to get duplicated with the language/en-US Url, and it turns into a bit of a mess. My changes get around this by assuming the language parameter for the default language, and removing it if supplied. It uses the 'other' (ie, non-default) languages, but gives you the ability to name a page differently (provide a different url, ie /beer, /bier and /cerveza ) which will drive the language parameter rewriting behind the scene. I have further work to do on the portal alias side, so that .com , .fr, .de etc can drive the language parameter as well, all on the one portal and without creating duplicate content.
To be honest the most difficult thing about all this is coming up with an interface that makes logical sense for a user. And that's why it hasn't been released yet.