Channel documents for import support permissioning a channel to a user directly instead of a group, but the current channel export scripts don't deal with this use case.
Potential patch for this.
Patch was done against rel-2.6-patches with latest Cernunnos JAR.
Patch creates
<groups>
<group></group>
</groups>
<users>
<user></user>
</users>
Was able to successfully export in this manner, however, have not tried import.
Slight error I just discovered in my patch. In the section that adds the <user> elements, it needs to be
<append-node parent="${singleNode(users)}">
<user>${groovy(aMembership.getKey())}</user>
</append-node>
Attached new patch UP-2221.txt.
Resolved in trunk and will be merged into patches later today. Thanks Dustin.