Formerly Known as Newbie
Join Date: Mar 2002
Location: Helsinki, Finland
People tour with all kinds of bikes. One of the most toured guy, Heinz Stücke, covered tens of thousands of KMs on a 3-speed bike. I'm nowhere near those touring distances but have done many tours on a couple of Nishiki hybrid bikes, and my current tourer is a GT Traffic hybrid.
If you're comfortable on the bike, and if you can fit the required accessories (most importantly racks for panniers), you're good to go. BTW, when you pack all the gear you need for an unsupported tour and hang the panniers on your bike, you'll notice high riding speeds are no longer a priority. It's more a matter of being able to ride several hours a day, and that's why it's important you're comfortable on the bike.