dustylense
Veteran
If Final Cut (and other NLEs) can't handle the 50p/60p footage from the HX9V in a straightforward way then I would consider getting the latest version of Sony Vegas - Movie Studio HD Platinum 11 suite - as it can handle these frame rates. For around $100 (£75 UK) that's got to be worth a look. I understand Sony Vegas is usually very stable. Not sure if there is a Mac version though, need to check that out.
I just edited a HX9V project at 1080/60p realtime in FCPX. SO you're wrong. I had realtime motion and I retimed in FCPX no problem at all. I just had to transcode with a different program. After transcoding, I just imported the clips and edited away.