The first question should be what is wrong with the C-dale? You are riding the bike now on week long tours now, is there a comfort issue?
I know a guy who rode a Killer Vee down the east coast 4 years ago over 900 miles and he still tours on it. The only things he changed on his was the handlebars and stem to give him a more upright position. He also has a rear rack on it. He may have changed wheels also.
The bottom line is don't buy a touring bike because someone tells you want a touring bike. Buy a touring bike because
you want one.
If you want a touring bike obviously we take into account you are a big guy, IMO a 700c road touring bike isn't going to work very well for you , Most big guys I know are not comfortable on drop bars also a 700c wheelset is seldom as strong as a MTB's. IMO 26 " wheels are more durable and will handle your weight better.
Check out these offerings and see how they differ from your current ride. You may find your C-dale is only an accessory or two short of being one of these bikes
Here is an inexpensive 2005 touring bike that might interest you
REI Safari
Here is a higher end Koga Miyata World Traveler( my personal favorite)
http://usa.koga.com (click on touring)
Gunnar has a 26" touring bike with a suspension fork
http://www.gunnarbikes.com/rocktour.php
The absolute strongest bike has not been built yet. but a 1986-1992 Specialized Stump jumper is pretty close, many of them have been turned into touring bikes.