Sounds to me like the K-5 is not for you.
But can't the K-5 accommodate(up to) 64GB SDHC?
Either way, it is xDHC compliant and will certainly be updated to accommodate the larger cards, so patience is your friend here.
But what's with the noise issue?
I find the K-5 to be so very clean over that of our K200D, K20D and Kx.
Then again, I only shoot RAW so, that might have alot to do with it.
However... I've never encountered the continuous shooting issue you describe either.
I always find it "so very fast" on my end that it continues to surprise me. Then again, I turn off all/and every processing feature because I like to keep my files as basic as possible(for post).
As for video... you didn't buy a DSLR for video did you?
I know I didn't
As far as I can see, the K-5 is not a video machine.
Yes... it can do video. But that's purely a commodity as far as I'm concerned.
However, if I was going for a video camera that can accommodate lenses, then I would most certainly look at the Panasonic or one of the FF Canon's. Which aren't perfect either, but they seem better suited to the task.
Question though... didn't you know about video before you bought the K-5?
And finally... if you just bought it, I would certainly return it if I was in your shoes.
There's not sense paying $1500 for something that isn't working in your favor.