Using numberless substantives

Hi,

I'd like to know whether some one of you has dealt with a conlang
where three endings for nouns were used:
1 - one for the numberless noun
2 - one for the singular noun
3 - one for the plural noun

My idea is for a system where you normally use either 2. or 3., and
use 1. just for when you don't know whether it's plural or singular
(like in "do you have children?") or for generalizations ("roses are
beautiful / a rose is beautiful"), or for when you don't want to make
it explicit (there is a way to achieve it / there are ways to achive
it).=20
I've also thought that 1. could be used for indicating the abstract
sense of a noun as distinct of its concrete sense, as in "dance",
which may mean an action (concrete) or an art in general (the art of
dance, abstract). However, I wonder whether this distinction, not made
(at a morphological level, I mean) in the natlangs I know, could be a
burden if made compulsory for the users of the language.




Saludos,
Marcos