Spunjer,
I remember your post... it was a big part of what inspired me to look for this sword. Totally Awesome!!!
It is my understanding that indeed Bakunawa (from Bako [bent] sawa [snake], see earlier link) is a sea dragon as are most of the naga (as I believe, in the region tend to be associated with the sea). I too use to think that it was more human looking. It seems that the more variations of Bakunawa I see - I see new things, man like, hooded dragon like, bearded dragon like, bat like and almost dog like (but the nose is definitely bat like)... and is likely due to the influence in the different areas. I like the hooded dragon versions too. I believe you have seen all of these forms pictured on the forum.