For those of you who are early adopters and love testing new ROMs before they are ready for primetime, developer JoelZ9614 has just released an unofficial alpha version of CyanogenMod 9 for the HTC EVO 3D. Keep in mind that this isn't even a beta yet, so bugs are bound to be present.
Known issues right now include a non-functional camera, no 4G WiMAX, in-call mute not working, and the SD-card not properly mounting to a connected PC.
This same developer has also been working on a pure AOSP Android 4.0 ROM, as well as an Ice Cream Sandwich Sense-based ROM. In other words, he's been quite busy over the past few weeks.
You can give the latest CyanogenMod a try at the link below; full installation instructions are also available there. Just remember that updates will most likely be frequent as all the bugs get worked out, so I'd only recommend this one if you are ok with bugs, and you also consider yourself a flashaholic.