Quote Originally Posted by bitpicker View Post
Really? Нос being masculine, isn't носище neuter? Is it always -ище or is it -ища for feminine nouns?
носище is masculine. Well, in colloquial it can be used as neutral for further enlargement and making comic effect.
"-ище" is for masculine and neuter
"-ища" is for feminine.

Quote Originally Posted by bitpicker View Post
That's not in starling, but the other is. Now of course I'd like to know all the suffixes and how they relate to each other on a scale of giantness.
It is difficult. In colloquial extensive improvisations are possible so it is not formalized.
Anyway there is no scale.

As mudrets said, there are -ин- and -га suffixes but normally they are not applicable to "нос". All those suffixes mean basically the same but are applicable to different words and I don't know what are formal rules to select proper suffix for a given word.

BTW Italians also have "undiminutive" suffix -one.