Here's a tall .833" stem on ebay: http://cgi.ebay.com/NOS-SCHWINN-STEM...QQcmdZViewItem

I believe the description regarding the stem you linked to is a misprint.........I found a very nice SR stem a while back on ebay that's quite tall and also has the short forward extension I was looking for. I suspect all the .833" stems you're going to find will have a 25.4mm clamp diameter. The way I found the .833" SR stem I bought on ebay was that I noticed a more distinctive than is typical ridge near the top of the quill, apparently where the stem had been machined down from the standard 22.2mm size during manufacturing. The seller apparently didn't notice it was an .833" stem, there was no mention of it in the description-