blueing is simple, lye saltpeter and heat to get a real pretty but very short lived finish.....but i wouldnt expect it to apply well to the metals used in the spokes, without first being blasted, which of course weakens the spoke. the cost to powdercoat a spoked wheel is little or no more than a rim alone. I know you said you were dead set against powder so.....moving on. I like duracoat, easy to apply, many colors tough. but other options are available. most notably aluminum that you can either have anodized or do it yourself (anodizing is fun). Im afraid if its a just for looks thing you want, you may end up having to pay. my local shop will do multiple colors on a spoked wheel, rim spokes and hub different colors....i would bet that with the right shop you can get that glassy blued steel look with powder. good luck, it sounds cool.....black rims with that kinda swirled glassy blue spokes. i originally was going to carbon wrap my rims and black my spokes but am going alloy instead, but you got me thinking of spokers again.