May be a stretch, but this presented itself to me like a hybrid of a Mint Julep and Moscow Mule. I found it had much (cane) sugar flavor that made it seem more sweet than it probably was. I agree the key may be adding some appropriate, contrasting bitters.
Tasty and spicy. I might advise starting with a smaller amount of ginger beer and adding more, if necessary, to taste, as the bourbon was a little buried for me. (Especially since this balance will probably vary quite a bit based on your choice of bourbon and ginger beer.)
Added a dash of Peychaud's and it was absolutely delightful. Of course, sour mash, lime and ginger beer are some of my favorite things, so this one is definitely made for me!