I mean, hShop does exist (and as its own application), but if you're implying something akin to hShop injection into the eShop app, then it would definitely be a major convenience, but then again, they do both exist in separate accessible forms, so one could ask what's the point.

And there's also Universal Updater, which is essentially what you're describing: a "homebrew shop", which I assume is equal to the Open Shop Channel on Wii. But, again, they both exist as separate apps, so why would someone need to put in effort to go through with app injection?

Well obvious piracy lookout, as much as it is cool, "deez big 'eads keep saying it's bad for me when I can't do anythin' else and make excuses outta nowhere!" I assumed a homebrew frontend for UU, but best of both worlds in one will be good.