Who Makes Custom Chips?

toybuilder asks: "I have an idea for a neat consumer product that could benefit greatly from a really simple bare-die chip to reduce cost and size. I took a VLSI and chip design class back in college about 10 years ago, so I know how to design the circuit I want in CMOS. Now, I'm sure there must be fabs for older-generation designs (maybe in China/Taiwan) that I could have such a chip made -- I've seen bare chips in musical greeting cards and in tiny toy gadgets. How do I go about making my chip design into reality if I only want to make a fairly short run (a few *chips* during development, and maybe a 6" wafer's worth of the final design)?"