I've done mono bug runs in a lot of games, most recently White 2 challenge mode, and I've been a bug using league member on a facebook page centred around competitive. c: Ingame I tend to use more varied types for my first run, though. --- Official Scrafty Of The Black And White Clan. Official Lorelei of the BW 2 Boards. Official Beheeyem of the X/Y Boards.
Dragons, Poison and Dark. Currently doing a Poison type run on my White version and just got the 4th badge. --- http://i.imgur.com/EOXWVm0.jpg Do you wanna be cool? Join the Reservoir Dragons! Support Draceon for 2013!
For the story, I often do that sometime after my first playthrough. And Mono-type teams are definitely viable if you play where permanent weather in combo with some abilities are allowed. (Snow Warning + Ice Cloak, Drizzle + Swift Swim, Sand Stream + Sand Rush...). I used a mono-ice team for the longest till Snow Warning + Snow Cloak was banned.