For myself, I find that the only problem when selling custom-made things on eBay is I can sell 10 less-expensive, high profitability items in the time I can sell one custom-made item.
I recently tried selling hand-crafted 2 and 3 cigar count pocket humidors, made from exotic woods with COA signed by the crasftman and the market just wasnt there at $60 US
Yet if I were selling ones made from tin made in India costing me $2 each for $15 US, I could probably sell 100 in a month.
I find that my market for musical instruments lies in the $150 to $400 US range. Anything below that and it isnt worth my time, anything more than that and I list the instrument 3-5 times before selling it, maybe.
I am looking at one of my supplier's brochures right now and see they make Paisely gig bags and coloured ones in tan, red, rust, purple or blue as well as leather and leatherette/vinyl.
However none of them would be my choice as a Buyer or as a Musician. There is nothing that distict about them.
Some of the cases for DJs carrying their LPs or CDs are good examples of pushing the edge a little with brilliant colours of more notable patterns and materials.
Anyway, you know your market better than I. I just hate the normal, run of the mill, status quo all the time!
Malcolm