I just spent a little time writing and testing some examples (both CFMX and JSP).
I used taglibs from various sources.
The examples worked as expected, in both CFMX and JSP.
It may be that deploying tag libs is not available with CFMX Standalone, Professional version. This version is not available on the Mac.
The earlier Linux port, and the current CFMX for J2EE Developer edition for Mac OS X, are both Developer versions of the product(s). As such, they both are full-featured versions. After 30 days they restrict external access to a single IP address.
So, again, you can deploy taglibs within ColdFusion.