Hi Steffen -
My apologies for the time it's taken to get back to you on this one.
I've had a look through this project and concluded the reason behind the build failure is NCrunch's lack of knowledge about the customisations you have for your FSharp build. Basically, NCrunch doesn't know about the FSharp build binaries stored alongside your project, and therefore it doesn't copy them over to the workspace at build time.
To work around this issue, you'll need to make use of the AdditionalFilesToInclude configuration setting for each of your FSharp projects.
After setting the following two values into this configuration option, the entire solution built without trouble:
..\..\..\tools\FSharp\*.dll
..\..\..\tools\FSharp\*.exe
Give it a try and let me know how it goes :)
Cheers,
Remco