Hi everyone,
When I updated OF for iPhone to the latest version, I noticed OMNI updated the icon. It's similar to what I've been using all along on my desktop copy of OF.
Here is the link to the icon set, along with icons for other apps in a similar style. Enjoy!
http://barrymieny.deviantart.com/art/isabi4-105473594
Due credit, of course, to barrymieny at dA.