There are a good number of dedicated motorbike touring holiday operators & organisers. Some organise guided group tours abroad. Others organise group tours or self-guided itineraries based around their own accommodation or motorbike rental services.
There are two lists...
My Rides - Chris Neary's route review & information site.
Motorcycle Touring - Two American riders writing about motorcycle touring in the southwestern states and Mexico.
The Fearful Adventurer - Torre de Roche writes in her travel blog about her occasional experiences, mostly on the back of a bike, travelling in the Far East.
The Texas Rambler - Retired couple tour USA on their Honda Goldwing
RoadRunner - Motorcycle touring and travel magazine.
Ultimate Motorcycling - News and review site with a touring/travel section.
Bikers Are Welcome - Guide to biker-friendly accommodation in the UK and Europe.
Motorbike Europe - Major guide to motorbike touring throughout Europe and beyond.