You need to qualify your statements as this is not a true statement without a lot of caveats. Prior to 1999 it WAS a true statement and as of this year it is once again a true statement. However, from 1999 through 2008 model Cannondale's M/S, L/S, and XL/S frames had the SHORTEST stoker compartment offered by any of the major builders at 27.1" vs. Santana's 27.75 and more recent 28" stoker compartments. The X/M would get you a 28.1" stoker compartment and the J/L would get you a 29.1" stoker compartment. They finally fixed the smaller size frame length issue with their 2009 models by upping the 'small' stoker compartments to 28.6" to be on par with Co-Motion.

Santana has some specific reasons for why they use the length of stoker compartment they do on their tandems and it has nothing to do with tubing limitations. If you'd like to know what they are, give Steve Leesse or Bill McCready a call at Santana and they'll share it with you. If suffices to say, if a Santana client wanted a 30" stoker compartment on a Santana they can and will built it and if it needs to be extra stiff, they'll make it extra stiff. If there was an outpouring of interest by Santana's clients for longer stoker compartments, Santana would probably reconsider it's design spec and find a way to bring the desired product to market. They did the latter with carbon forks, disc brakes and low-spoke-count racing wheels for that very reason (customer interest and demand) so it's hardly a business constraint.

As noted in other threads, Cannondale has always built a very nice tandem using oversized, straight gauge tubing that is well-suited to what you have described to be your team's extremely high weight. However, for teams of more average weights in the 290 - 360 lbs range Santana's tandems are more than suitable for most average teams and, to a certain extent even larger teams in the 400lb range -- both in terms of stiffness needed for performance and comfort which to Santana equates to endurance.

Again, I believe you indicated your personal weight was well over the average tandem team weight and when you add a stoker of average size / weight to the equation you're clearly a team that's pushing upwards of 500lbs. Teams like your own that are skewed well off the center of the bell curve -- at the high or low end -- will always have riding impressions that are equally skewed. Therefore, in much the same was as teams that weigh only 250lbs will likely find most frames to be more than stiff enough, it will truly be rare for someone of your team's size to find many tandems that will inspire confidence in handling and frame stiffness.

I can actually agree with part of this statement, but it's about the only one.