When this one started getting brought up, I ran the numbers and came up with about 11k a month, which I personally think seems kind of low considering there would be a 10% tax on all sales. As to what that looks like if we change the fee to 10% (which I personally think is way too high) who knows. It would likely just end up with less market transactions. Not sure the juice is worth the squeeze on this one. As @jarvie suggested though, perhaps a poll would be better for this one.
The main purpose of running this one is simply because I ran the alternative. I can't only run the ones I like/agree with. 10% seems crazy, but this is what people were suggesting. I'll set up a poll tomorrow and see how/if people want to revisit this one by reapportioning the 6% fee that already exists.