Bought my orthotics at the "Good Feet Store" about $200. They are for normal shoes but will fit in dress shoes (I have to dress up for work). Took my cycling shoes into the store with me to make sure they would fit. You can go to a podiatrist and get a pair that are custom fitted but for a lot more. These come in a variety of sizes and stiffness.
Doc, you really must know your stuff, I could barely follow what you said. Yes, I've noticed that my feet do go numb on the elliptical trainer. That sensation is more like the whole foot going numb. As for just toes going numb, just my anecdotal experience and the person who originally posted never did reply, but if your pedal stroke isn't correct, and you are dipping your toes on the down stroke, then yes, your toes do slide to the front of the shoe. The pain I was experienceing could be described as someone pushing a red hot wire through the middle of my foot. Since I got the inserts, no more pain. I can now ride 50, 60, 75, and 100 miles okay. Before, at 40 miles or so, the pain would start in and even finishing 50 miles was pretty hard.