Nothing needs to be local. Kernels and initrds must be on a mounted filesystem.So only NFS is supported for making kernel and initrd appear local. HTTP can't be used to copy them locally automatically. --path=http:// is illegal - should it be?
It doesn't really make sense to me that --available-as= allows http,nfs,ftp but --path= only allows local paths (well, an NFS mount isn't local but appears local).
Trees can be local or remote (if remote, ftp, nfs, or http access is required).What's your definition of Tree?
When I inspect a distro, say CentOS-5.3-x86_64-bin-DVD.iso, I see kernel (vmlinuz) and initrd (initrd.img) in the images/pxeboot/initrd.img directory. Do you consider the CentOS directory the "Tree"?
Paul