Agree that the main thing to cover is repatriation if it all goes wrong, baggage and bike cover is usually poor and only payed out if you are mugged most other instances your gear was "unattended" even if in a room.
The main thing that will affect your choice in insurance is the lengh of the trip and and where you want to go (USA/Canada can be alot more expensive). Most insurers drop off at the 12 month point pretty much the rest at 18 months.
Read the small print well and contact the company and tell them you'll be doing cycling touring as a primary activity this also seriously affects the price with most companies.
I did alot of research before my trip....here are my findings....
http://shanecycles.com/cycling-info/info/bicycle-travel-insurance
Good luck, its a mine field out there......