Look at Akainu and Aokiji. They aren't really like Ace and Kizaru… I think a mud logia would be really special.
I think logias don't really become intangible. They become their element. Of course, if it's fire or light, things go through. (Maybe they can be just burnt, in Mera Mera's case) If it's ice, magma, or even mud, it's different. I think you won't ever see a hole in Aokiji's body. (would be great, though, if only a part of his body would break ^^)
But judging from what we saw, Caribou can still be a paramecia.
you are right, it could be paramecia (I WOULD LOVE IT IF IT WAS PARAMECIA!)