JUST TO UPDATE EVERYONE:
I got the memory card I mentioned in the beginning of this post with the 95 MB/s speed and when recording at bit rates above CBR 1.4x with audio enabled, it still stops recording after maybe 5 seconds or so. But I can, however, record all the way up to CBR 3.0x WITHOUT AUDIO smoothly and without the card stopping at all.
So it definitely is a MAJOR improvement over my last card which was only a 24MB/s card.
In a "perfect world", audio would be recorded in its own external device not built in to the camera anyway, so for controlled situations such as interviews, landscape shots, and whatnot where you would have a lav mic into a recorder on the interviewee or just the device to pick up ambient noise.