Never seen one. I was under the impression that the better the quality of grain, and the denser the wood, the better the sound would be and the longer the sustain. Hence, wouldnt an oak guitar sound the t*ts?

Is it just the weight that would be a problem?
Oak is a very porous wood which makes it hard to finish. How heavy oak is has nothing to do with it because mahogany is just as dense as oak and mahagony is used all the time. Oak would probably sound good because its dense but at the same time sound bad because there is a lot of air in the wood because of its ring porous nature.
Quote by Stiffy Maximus
i smoke some weed and get naked. thats the way to write a good song.
Nah I just meant that it might be a bit of a backbreaker to play
PRS Tremonti SE with PRS USA Tremonti pickups
2001 Ibanez RG470
Peavey Bandit 112
Fender Superchamp XD
USA Jackson SL1
Im pretty sure thats what brian mays guitar is made of but yea it would be like having a concrete block on a strap.
^His is actually a semi-hollow.

From what I've read, oak doesn't really resonate well. May's is a fluke, as it's not ALL Oak. It's just a weird guitar in general.
Here's one of my posts about it:
You can search for more, if you want. There was this month where everyone wanted to build oak guitars...
Oak isn't a great tonewood. Maton have experimented with it, and plenty of people have tried making their own oak guitars.