I am not sure exactly what style would be traditional manga style, but I'd say the idea of applying both seems pretty interesting.
Certainly worked for Fullmetal Alchemist and it's peers, using a more realistic style for grave situations and a chibified style for silly moments or confusion.
It's also possible to alter styles between characters ala Lucky Star, but to do such may be jarring in the long run. Worth to mention, though. :3
EDIT: Also, yay for Lying! Sorry for missing your post, I was distractamated by Watching a Let's Play instead of being productive. ^_^'