fstack should be able to take a core file and produce a stack trace of it.
bash-3.2$ ./frysk/bindir/fstack core.$$ /bin/bash
#0 0x00110402 in __kernel_vsyscall () from .../[vdso]
#1 0x0807bfa8 in wait_for () from .../bash
#2 0x0806eedd in execute_command_internal () from .../bash
(tested in TestFstack)