I've seen people done this before and here are some tips that I think might be useful
1/ Before you mention any channels, make sure you let them know!
2/ Create a template or document and send to those channel owners to sign it (to make sure they own or have rights to use and show all the materials in their videos) so that you can reduce the copyright problems.
3/ It will be a great idea to do a video where you interview a "best of the week" channel through Skype once a week. This will help you bond with other Youtubers also create a healthy competitive atmosphere.
4/ Mention channels in groups or categories. For example, if you talk about art channel, then your whole video should be about art channels, if it's about vlog, then all vlogs. This will make it easier to see the different between channels therefore more knowledge about creating Youtube channel in a specific activity.