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

Plan on making two amp stands and a rack out of wood and granite. Looking for suggestions for heavy duty cones/spikes/feet for the base. Main concern is that they can handle the combined weight-probably 400lbs. or more.
Any ideas/resources will be appreciated.
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,
Look at They have some pretty nice brass footers.