The rubber Hogues are about the same thickness, but have a different shape that really feels different in the hand (more flattened out, vs. the stock grips being more round).
I have big hands yet find the 92's thickness to be my only real complaint. I think Beretta was trying to create a pistol reminiscent of revolver grips--but it just doesn't work for me
I bought a pair of Hogue NYLON (hard plastic) grips as well, and found that they are pretty easy to sand down and contour to the necessary shape and thickness (subject to the screws of course). I did it with mine, and with some stippling afterwards, they look and feel pretty good. You can usually find them for barely over $10. Good luck!