I got the MR3-S Frag Rack from blackrockreef.com a couple weeks ago. I gotta say, this is one solid piece of craftsmanship and a real work of art. The design is simple and sleek and I think the hex shaped holes give it a really unique feel. Also, the rack uses neodymium magnets to hold itself up, which are seriously strong. I feel like I could use some real force on this rack and it wouldn't budge. There's room for 19 frag plugs on this rack and the spacing is perfect.
Here it is in my tank (sorry, iPhone pic):
Here's a couple pic from the site to give you a little better idea of how it looks:
I got the onyx black, but it also comes in a neat clear version:
The MR3-S is the smallest rack. There is also a MR3-M version that holds 31 plugs, and the MR3-L that holds 46. I think the prices are incredibly reasonable for something that'll last forever. The S was only $25! The M is $30 and L is $35. Also, shipping is free!
The owner (screen name Sushi) is a member of many reefing forums and personally answered questions I had about the rack.
I'd strongly recommend this frag rack to anyone in the hobby, and especially for any zoa/paly enthusiasts like me.