I have a g&g l85. Head over to the sa80 page on Facebook, always people selling them second hand on there. If you decide against bulpup in the end I personally like the g36 for weight and balance and they are fairly easy to mod.
What improves accuracy is a combination of things. Better barrel 6.03 or 6.05 should work well but buy a decent make. New hop up chamber. G&g green bucking and nub works well. And if your looking for more range you can look into flat hops and r hops.