the string stop you show by itself could be radiused on all edges to soften its look and even given a different finish to either match or contrast the xbow. are you happy with the length of pull for the stock? if you are looking for more length then maybe a nice piece of hardwood or brass to space the butt. brass can have some lightening holes in the interior to reduce weight. you could also make wood foregrip panels to fill in some of the skeletal front and to help blend in the string stop. I would solder the cable ends to prevent untwisting and maybe even solder on some brass or copper ferrules to decorate the ends. how hard is cocking it now? perhaps an extension under the fore end to provide a little more leverage? something a bit like a backwards bayonet. I've always like the look of shotgun scopes with the lack of the front bell, and the reduced magnification makes it easier for me to find the target quicker, but I'm blind as a bat so pinch of salt. about the only other thing might be some sort of grip cover, so you don't end up with a black palm from the aluminum or cold hands from the metal conducting away the heat. also, instead of a filler in the fore end, maybe a palm block like on target rifles, sort of like an airforce awacs radar dome but in wood and under the frame. maybe with some subtle finger grooves for better ergonomics.
It takes some strength to cock it especially when I have a 3/8" spacer behind the prod. My problem now is the prod is a little to powerful, about every five shots the bolt at the nose of the crossbow that holds down the prod strips out. This has happened twice, I'm assuming because the aluminum can't take the steel prod vibrating once fired, I'm thinking it kinda pushes the bolt forward in it's own threads cross-threading the bolt.
