All CSR GSD4e (SiRFStar 4) are marked as 48 channels:
And nobody would ever need more than that as GPS has only 37 allocated PRN IDs
You may look here:
http://michelebavaro.blogspot.com/2011/ ... rrier.html
for a non-exhaustive list of antenna-less modules; depending where you live, some may be easier to buy than others.