Does anybody out there think they have any bit more insight as to whether Hearthfire's houses are TRULY going to be FULLY capable of being designed and built from the ground up, or whether they're just going to be ploppable pre-made rooms that can only be connected to each other in what ever configuration you want...??

From what I've seen and read, I've interpreted the case as only being ploppable pre-made rooms which can then be connected to each other in what ever configuration you want.
...If that happens to be the case, then Hearthfire may not be all it's cracked up to be... Sadly.

...I would hope it's not the case though.

I just hope for different architecture styles.

in the vid it shows you making wall by wall plus got the feeling beth is hiding something

It's not exactly GECK. I would be fine with pre-made room, as long as they allow a lot of decorations.

And blood-stained wallpaper...

Maybe you can build-up the peices into prefabs to make things easier to keep track of.

And I hope you can craft wall shackles?