This is kind of like it. It's manila for the Titan using TouchFlo 2d. This is a full custom rom from Scott Crosler. I use it and love it. It's not EXACTLY the Diamond but it is as close as you can get for free and have a speedy device. Go with the "Loaded Edition" in the top left corner. I haven't donated to him yet, but I will after I get back from my Vegas trip. It's worth it.
http://www.scottcrosler.com/Titan.html
To use the Internet tab you have to install Opera browser afterwards. If you need help, PM me.