Not sure for Gunship, never tried in 25-man and I don't know the encounter well enough to guess if it is doable.
I think that Festergust and Lana'thel have too many hp to be soloable if you can't avoid their "solo enrage" mechanisms, and I can't think of a way to do this as a warrior.
Valithria 10 is already a problem, Valithria 25 won't happen until someone come up with a very good idea.
The other bosses should be doable. Even in 25HM for some of them.
Edit: Now that I can record in a good quality, I re-recorded some fights and started upload content. I still plan to do "all the raid boss of the game" and I wanted to do it in chronological order, but I can't be bothered to record/edit vanilla content today. So, Cataclysm it is!
Magmaw:
http://youtu.be/2R40VJXXAc0
Omnotron:
http://youtu.be/DAT6z0iuWdQ