I have all 28 Unown in Gen. IV. If you want a certain letter, ?, or !, let me know. I still have some that I haven't imported to Unova, so I can include yours in a batch.
Note that it will be cloned as caught as Lv.5 and they all have different natures (we can go by that too if you want). 1 in 26 is not what I call good odds in finding another in the chamber, though ! I think is common in the case of the symbols in the entrance room.
Oh, and the Unown can be free. I have a full Pokédex. :)