It doesn't seem like this process gains anything from using Dave Cheney's script or having a separate Go installation.  I think we can make it simpler -- the essential pieces are really just..

One time setup:
* Installing Go from source is required (e.g. a binary download will not work here) 
* Figure out the values of GOOS = [darwin, freebsd, linux, windows] and GOARCH = [386, amd64, arm] for your target platform
* Build the cross compiler for your target machine: cd $GOROOT/src && GOOS=x GOARCH=y ./make.bash 

To cross-compile:
* GOOS=x GOARCH=y revel package my/app