FBIDE didn't work on anything but windows, either. It COULD be compiled in Linux, but it was extremely error prone and didn't work well.
I've been able to compile FBIDE under Linux and used it for several months. All you needed was wxWidgets and all its contrbs compiled by yourself.
Windows API, which is used extensively in FBEdit and it's AddIns, is not easy to translate to something Linux can use. If you are up to the challenge, by all means, go ahead.
I know that it's impossible to modify FBEdit to make it work under Linux. It's a Windows project, made by a Win32 API specialist, so it will work only on Win32. So it's not the IDE that FB needs. I don't have the time to start a so big project, so for the moment I will stay with SciTE, that works well, although it lacks the advantages of a true IDE.