efficient cloning

Is there a way to accomplish the effect of this script w/o having to download any unnecessary objects?

================================================== #!/bin/bash

lt="/gits/linux-2.6/.git"

if [ $# -ne 2 ]; then
    echo >&2 "Usage: $0 <repo> <target-dir>"
    exit 1
fi

git-clone $1 $2
mkdir -p $2/objects/info
{
 test -f "$lt/objects/info/alternates" &&
 cat "$lt/objects/info/alternates";
 echo "$lt/objects"
} >"$2/objects/info/alternates"

cd $2 git-repack -a -d -s git-prune-packed ==================================================

I tried to modify git-clone to add an alternates file before calling fetch, but that file just gets deleted.

I presume I need to clone -s -l the local alternate, re-parent it to the new URL and grab anything missing, but how can I assure that it results in exactly the same repo as this script?

I'm often behind tiny straws, so efficiency is important.

-JimC