Reasonable price for bike carb manifold?

I have bike carbs fitted to my e28 518 using a manifold I made from a flange and some step down steel tubing, it works really well but looks turd. What I want ideally is a new manifold where each pipe leaves the flange and sweeps towards the front of the engine and then back. (So four small slight s shaped pipes with only a slights curve) just so the carbs don't foul my servo. I'll also need a small pipe leaving one of the pipes to go to the servo. I want this to be made of ally to a good standard. How much should I expect to pay? I have another flange here for whoever makes my manifold to copy in aluminium. One more time.. Flange.