Although we do, we arent able to put shulkers in /bp, which is a huge downside
This is a limitation of the plugin we use, which arises from the fact Spigot stores items weirdly. While there is an option for me to enable shulker boxes to be placed in backpacks (although it's technically possible now due to a weird glitch), the plugin author very strongly recommends against it, as shulker boxes in backpacks can break and cause all their items to disappear. I've left it disabled to avoid people complaining when things break.
As a side note, one workaround could be to store the most common items in your backpack, and put an enderchest in your backpack to access your shulker boxes that way for when they're needed. Considering you'd have to put a shulker box down anyway, it's not too bad of a solution (not saying it's a great solution either).
In regards to the donor perk, it's definitely something we can add. The specific tier would be up for debate though, but I agree with Yvette and Ako that $50+ could do with more perks adding to them. At the moment the only additional perks on top of the $20 is the ability to have bold/italic/etc nicknames, more homes, and a tag. Since we added those donor ranks, they've always had a note at the bottom saying they'll get more features in the future.
