Yep to both of the above. The Stillwater sporrans are probably drum-dyed--meaning the leather is saturated with dye during the processing, so lightening up the dye would be almost impossible without doing horrible things to the leather.... Leather paint (usually an acrylic base) would work but would give a different look. I would vote for the bunny dress-up, you can get a brown rabbit pelt for about $4-6 that would have sufficient size to cover the front panel. Or perhaps you know someone who makes sporrans?

Moosedog