I have my silly little addon that I've been using to learn and it is working with the v1.0 FuBar API:
CloakHelmToggle 0.3.0
I am having a bit of trouble getting it working with the v1.2 API though. I managed to get most of the kinks worked out when I started using Metrognome, but there are still some updating issues that I'm not having with the v1.0 FuBar API version. Specifically the checkable menu items with Dewdrop are not all updating when clicked on.
It's most likely something I'm doing wrong or have neglected. If anyone wouldn't mind looking through this and giving me a tip, I'd appreciate it.
edit: Sorry, I've placed the 0.4.0 version as an attachment to this post instead of as a Filefront download. I just didn't want to upload it to wowinterface until it was working.