I have one I bought years ago at an antique fair. The stall holder made them herself from pieces of vintage fabric, very solid and beautifully trimmed with fringing. It's now worn through to the lining on one side and I have had to turn it over and use the bottom instead. I haven't seen that stallholder for some years so don't think I can get another one.
I remember reading somewhere, that "in days gone by", they used to fill pincushions with dried coffee grounds - might be worth a try?
The problem with magnetic pinholders is that the pins themselves get magnetised in contact with it, and when you try and pick up one pin, you get two or three others stuck to it.