Actually, it's not that hard to acid-etch glass, particularly if you have a dot-matrix printer or an old pen plotter.
You can get acid etching paper and acid from a detailing supplier. The way it works is that you draw your image into the paper with a stylus, scraping away the coating, lay the paper on the glass, and then brush the acid onto it. The acid will eat the areas of the paper that aren't coated, and into the surface of the glass.
That's where your dot matrix printer/pen plotter comes in. Draw out your design on your computer. Take the ribbon out of your dot matrix printer, or put some dead pens into your plotter. Feed the acid paper into printer/plotter, and the pins/pens will perform like a stylus.
Or mask the design (like masking a flame paint job) then sand blast (best to use a spot blaster rather then an industrial blaster) that part or use a dremel.
Both acid etching and sand blasting are good. They will produce a little different result. Sand blasting will show up better but looks a little white. Etching will look a little "softer". If you sand blast you can use clear contact paper to mask the glass and then cut the design. Just make sure you get all the air bubbles out or you risk blasting a hole though the bubble and onto somewhere you don't want it to be.