I've been interested in these myself recently, although I won't be buying one! (cost!)
I think the
Panasonic HDC-SD5EG looks interesting, it records to SD (I think they do a HD or CD version too). I think it is based on similar technology as the Sony you may have been looking at.
The current problem may be software support for AVCHD, I know the new version of iMovie supports it and a couple of the PC apps, but stuff like Premiere doesn't currently work, I think Adobe say they plan support.
I think this technology will kiss goodbye to good old miniDV, esp. as the price of SD cards fall.
I would be very interested what you think if you go an try out a few!
Cheers
Cris.