With Tenu's monumental archival effort (who backed up almost every single Crysis map and mod before the website was remodelled) I was able to cross-check every missing map from pack 15 and download them from his archive. Which sadly I cannot link, it can however be found in the comments of the Drivers Hell Trilogy :)
Contains almost every map from pack #15 on gamershell, although I could not find a select few despite my cross-checking efforts.
I only have pack 19# to go, and thus the mappack series will be complete! Stay tuned! :D