DIY Amp Stand/Rack-Cones/Spikes/Feet?-Suggestions

Look at www.mapleshade.com. They have some pretty nice brass footers.

If you're making a Flexi style rack (threaded rods as uprights), there are a number of feet available on the market...

For that matter, you could also:
-have them made yourself (any machine shop)
-just sharpen the uprights to a point (or a hemisphere which will also give single point of contact on a hard floor or disc, but can support more weight).

Good luck,