I've tried it many times and nothing approximates velvet. Any ideas?

I would love to hear any ideas as well so, here's a bump.

I have no idea. But, would love to know.

I wish I could help, that's something I'd like to know too for future reference.

I would love to know too! Maybe if you moistened it lightly somehow with something (lotta help there) and then found a way to dry brush or spray dry black luster/petal dust? Maybe a light coating of thinned piping gel and maybe use a big poofy brush to blot alternating petal and luster dusts to get the velvet effect?

I don't know, just brainstorming.
You could try it on a small patch to see if it works.

When you figure it out, let us know!

I saw on one of the many cake shows (not sure which one) they sprayed fondant with cocoa for a brown suede look - not really the same I know - more brainstorming - I would love to know too - heres a bump!

Depending on how big, maybe you can spray it with vodka and roll it in cocoa powder or pat the powder on somehow. Like the post before mine said. That is more suade but it may look good.

Black petal dust?

I asked this question last December and kept the response:

Get some petal dust or powder food color and a sea sponge from a craft store. You want to add some grain alcohol to the color to make a fairly thick paste and dab it all over. You want a section to dry before you attempt to go back over it if needed. With a little practice, it'll look just like velvet.

You can make any color, but the trick is to start with a paler base color for the fondant.