I have my main toons in a raiding guild, and multibox teams in a guild i made for gbank. gbank is so handy when leveling. Will probably create one or two more as I level other teams up.

A lot of people respect the fact you can multi box, it means generally your very aware of your environment, watching lots of things at once etc.

If you want to get in a good guild you will have to get experience, achievements for doing raids via pugs etc generally and show a really good knowledge of your class.

On the other side of things, you don't need to tell them either.

If your planning on leveling your 5+ teams to 60 and also level a toon to 80 after\during that and gear it up and pug raids to get experience and then join a guild.. you may find Cat is out by then. Well maybe not that bad, but it all takes time. Boosting to 60 doesn't take huge amounts of time. beyond that it takes a bit.