Hi, try Parts Express.

Here is a link to a search result there for "spikes."

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3

If you'll place "DIY loudspeakers" into a search engine, you'll get more versions to choose from. Obviously, you'll have to wade through some sites to find the spikes you prefer but many DIY sites also sell spikes.

Are you putting the flexy on a rug? if not, one option is to get a large nut, or better yet a sleeve, that will fit the bottom of the legs of your stand. As someone has recomended in another thread, Place a glass marble in the little cups they create. the surface area contact of the marble should be a point not too different from a spike.

good luck.

PS, I previously built a flexy rack, but have recently switched to just wall mounting as much as possible by drilling directly into the studs. So far I'm much happier witht the wall mounts, especially the turn table.