problem with packaging Java program (clapham) for EL6: noarch vs. ExclusiveArch

[Eric Smith]

My package for clapham, a railroad diagram generator, was recently approved:
     https://bugzilla.redhat.com/show_bug.cgi?id=668240

There's no problem with Rawhide, F15, and F14, but I ran into a problem 
with EL6.  The package is noarch (being pure Java), and it seems to be 
fine with i686 and x86_64, but he update system notified me of broken 
dependencies for the PPC64 arch:

package: clapham-0.1.003-4.el6.noarch from fedora-epel-testing-6-ppc64
   unresolved deps:
      java>= 1:1.6.0
      batik

I expect that this is true for other architectures as well.  The problem 
seems to be that the batik library only builds on x86-64 and i686 (using 
an ExclusiveArch tag).  Perhaps that is due to java-1.6.0-openjdk not 
being available on other architectures, though I didn't research that 
since the lack of batik is sufficient to prevent clapham from building.

I thought perhaps the appropriate thing to do would be to add the same 
ExclusiveArch tag to clapham, but that results in not being able to 
build at all, apparently because of clapham being a noarch package:

$ rpmbuild --rebuild clapham-0.1.003-5.fc16.src.rpm
Installing clapham-0.1.003-5.fc16.src.rpm
error: Architecture is not included: noarch

Is there some way to have a noarch package that only builds for (or is 
only pushed for) specific architectures?  Or is there some other correct 
resolution for this kind of problem?

Thanks!
Eric