My strong recommendation for Spendor speaker stands is Sound Anchor. Heavy steel, spiked, rock-solid, beautifully made. I have a pair under my Spendor SP1/2E speakers (similar in size to the SP100's), and they work great.
I am using the Mapleshade Quadrapier stands for my S100s. They are maple and have large cones to couple them to the floor, I much prefer them to the original stands, which were , in fact, made by Sound Anchor. Mapleshade also has some low stands which I intend to try but haven't yet. They also have a return policy, take a look at their website. I am using the S100s and SP1s and they are not similar in size. I assume that the SP100s are the size of the S100s There was a recent article in HI-FI News [Aug. 2002] about the resonance patterns in metal stands, even tho the ones tested weighed over 30 kg. each and were filled with sand and lead they still had resonance problems. I don't know if this is the reason that the wood sounds better but to me it does and is better looking also.
yes,i'm a metal fabricator and built stands that would hold up a building!!their 23 inches tall and weigh in at a whopping 100 lbs.yep thats 100 lbs each w/o sand or lead!i have em sitting on brass spikes.painted them satin black, truley a work of art.sp100s kick ass with mc275gow reissue and c22 reissue mr71 and a mcd7007 bi wired with balanced inter.if interested in a pair get in touch.by the way you can fill these stands