tsrpm is great for cross-compiling but because it is implemented primarily as a bunch of perl scripts, it handles certain tasks slowly. One of those tasks is dependency checking.

Dependencies can be just as easily checked using plain vanilla rpm. Put all the RPM files you want in your RFS inside a directory and run this on the command line to check for missing dependencies:

$ rpm -Uvh --test --ignorearch *.rpm

It's much quicker than using tsrpm to do the same thing, and gives the same results. If there are dependency errors, you will see them -- if there are none, no actual install will happen.