It's trivial to modify the MuNPEx JAPE rules to include information in the NP annotation as to whether the noun phrase is singular or plural, but I think this is a useful feature when using NP annotations to assist in coreference and anaphora resolution.
I split the 'head' rule in en-np-parts.jape into two rules, one for plural heads (NNS, NNPS, PRP where the string is we|our|their|they|yours|theirs|ours) and one for the the rest. I added a type=plural|singular feature to each. This is copied over to the NP annotation in np.jape.
Cheers
Phil

good idea
Hi Phil,
Good idea, I'll try to add this to the next release. Just have to test how this works out for the other languages (German, French, etc.).
Cheers, René