We stayed in 12506 on The DREAM and loved it! (I believe both the Dream and Fantasy have the same layout)
I've posted pics a few times which I'll try to locate and have many more to share if you'd like.
Here's one thread:
http://www.disboards.com/threads/dream-concierge.3376714/page-3#post-53024127
which shows breakfast on the balcony while docking at
Castaway Cay.
Also from that thread on pg 6 - more balcony shots:
http://www.disboards.com/threads/dream-concierge.3376714/page-6#post-53037408
We had 12506 (cat T) / 12508 (cat V) / 12510 (cat V) / 12512 (cat T)
which are the only 4 bump-out verandahs on Deck 12 starboard - shown here above the rainforest spa hottub area on Deck 11.
(there are 8 more concierge staterooms with the larger verandahs on the port side - 4 on Deck 12 and 4 on Deck 11)
Starting from left to right:
12512
You can really see the difference in depth to our next door neighbor cat T stateroom 12514. (on the left in this photo.)
If you look again at the above photo, you'll notice we opened up the partitions between the 4 balconies. You can see how narrow the spacing is.
You can also get an idea of how long the balcony of the adjoining Cat V stateroom 12510 is.
12510 and 12508
unfortunately, I seem to only have the one photo here, but the balconies are identical for these 2 cabins. These sit as side by side cat V's. (non-adjoining) I seem to recall there are much better pictures of their balconies already linked or posted previously in this thread.
12506 (our stateroom)
here you can see cabin 12504's balcony size next door and beyond their partition is the beginning of the Roy Disney Suite's balcony which has the full clear plexiglass shield with no visible ralings.
again, you can see the length of the balcony for the adjoining Cat V - 12508 here.
I will look for the interior shots next.