Skinnying up a fat install

[Philip A. Prindeville]

I did an initial install of both .x86_64 and .i386 binaries for FC3 to
an Athalon 64-based system.  Now that I think about it, it would have
been easier just to have done a .x86_64 install, or limited myself to
whatever binaries weren't published in .x86_64 format.

So I find myself with various duplicated packages, like:

aspell.x86_64
aspell.i386
...
zlib.x86_64
zlib.i386

etc. and was wondering if there's an easy way to back the unnecessary
stuff out.  I looked, for example, at removing aspell (since it should be
fairly stand-alone) but that wasn't as easy as I thought:

[root at media ~]# rpm --erase --test aspell.i386
error: Failed dependencies:
        libaspell.so.15 is needed by (installed) gtkspell-2.0.7-2.i386
        libaspell.so.15 is needed by (installed) gnome-spell-1.0.5-6.i386
        libaspell.so.15 is needed by (installed) kdelibs-3.3.1-2.12.FC3.i386
[root at media ~]#

Is there an easy way to figure out (even if it's non-deterministically or
misses some corner cases) what .i386 packages can be dropped from a
fat .x86_64 install?

Thanks,

-Philip