Interesting, so about 26 KB just for a ZeroCoin commitment and niZKP in the scriptsig alone. That's the same as from libzerocoin.
From Green's lab:
For 1024 bit commitments and an 80 bit security level, this results in a 20KB double
discrete log proof and a total proof size (including the accumulator proof) of
25KB.
http://fc14.ifca.ai/bitcoin/papers/bitcoin14_submission_12.pdf...80 bit security?