for clarification, which stem do you have? the single-piece stem or the two-part telescopic stem? the part number you provided is for the single-piece 1" quill steerer tube type.

http://www.gaerlan.com/dahon/stem.htm

the link for the everyday cyclist shows his modification to his newer, 1 1/8" telescopic type stem.


either way, what you want to do can be done. with the single piece stem you CAN cut it. I've seen it done. however, you will have to cut that stem just below the point at which it begins to taper, otherwise, it will not work. the best way to determine if that will actually work for your desired riding position is to do exactly as everyday cyclist did; buy a MTB stem and attach it to your stem and test ride it. if it works and attaches securely, then you can mark it and cut it.

if your stem is the telescopic type, you can simply remove and measure the diameter of the top section. once you have accurately measured that tubes diameter, you can obtain a length of tubing the same diameter and gauge from a local hardware or plumbing supply store. this way, you will have a new stem while preserving the original.