Hmm, not sure how the "None" option under "Armor Type/Color Region" works. Might just be a non-functional default value that you have to change to something else for the rule to work? I would expect it to say "All" instead of "None" if VI had it working that way. (actually wouldn't be a bad idea to have a "All" on that list! You should make a feature request.)
Some armor types have more color slots than others, are you wanting the entire thing to be this same color? I think that's gonna be tough to get into one single rule.
Do you really not care about what type of armor it is? If you'd be a bit more picky this might become easier, needing fewer rules.
This requires testing, but if you make a "Slot Similar Color" req rule that requires "Slot 0 Color = 3E0307" and "Slot 1 Color = 3E0307" will a item that only has a single Color Slot fail just because it doesn't have a "Slot 1 Color" entry? If the extra non-existant Color Slots don't cause failure, then make a rule that has like 6 Slot Color requirements in it, all looking for the same color. =)
Only other option I see would be "One Similar Color" and you just hope for the best.
