scp should have options syntax similar to cp. a recursive copy of cp can be made with "cp -R" and "scp -r" with scp. "scp -R" won't work. I suggest to patch scp to accept the -r option too.
did you try scponly ?
no, and scponly isn't installed by default. :(
since no other linux/bsd distro supports scp -R, doing so in Gentoo linux would introduce wrong incompatibilities imo