This is more a "kludge" than a DYI, but I found another reason not to cut a steertube. A friend of mine moving out of state sold me this mostly unused Trek 4300 for a hundred bucks, and I loved the frame right away because unlike my other MTB, it's large enough for me. But the handlebars were up way too high, so 'slammed' them best I could (without flipping the stem) by having the stem and spacers trade places and they feel much better, even though I've now got a dork-tastic couple inches of steertube sticking up.

While grocery shopping this morning, I had this nice little convention-giveway backpack with me, and set it down on the front rack while fishing my gloves out of it, and got the idea to wrap the backpack straps under the handlebars and over the steertube end to hold it in place, so the bag wouldn't fall off and bruise my bananas. Huh. Nice and snug. A perfect fit. Tie the dangly ends of the straps around the head tube and the thing riding solid enough for practical grocery hauling.

It's not very aero, but hills are much more a factor than headwinds where I live. I *really* hate riding more than a mile or two while wearing a backpack on my back, so I always like to figure out a way to put my loads on the bike instead. But I guess now I don't have to sweat what kind of rack bag I'm going to need to get for this bike : )