I don't think there are any true blue coleus. Just the way the pictures of some purple-ish ones are taken made them appear blue. I remember a flower catalog had a photo like that.

Thanks Dennis,
Yeah, you're right about that one. I've seen that happen in other catalogs with many different types of plants and flowers.
What originally caught my eye was this photo:
http://seattletimes.com/ABPub/zoom/html/2004445726.html
Taken from this article on the book, "Coleus: Rainbow Foliage for Containers and Gardens" by Ray Rogers:
http://seattletimes.com/html/pacificnw/2004445689_pacificplife01.html
It made me wonder if it wasn't really a blue coleus. I'd be suspicious of flower catalogs doctoring their photos, but not so much in a book on coleus.

That coleus is Religious Radish. You can google/bing it, and see it's usually pink/bright purple edged and darker purple on the inside. I read the book and liked it. Ray Rogers has an old website about coleus (only wrote in it 2007-2008):

Here is a link that might be useful: The Coleus Society