You haven't really stated your criteria for what makes the ideal bike, in your mind, so it's really hard to comment. I'll take a stab at it, though.
The MBB FWD bike is not one that you'll jump on and do an ultra distance ride. There is a learning curve, so I suspect you would dicount the Silvio right away. Once you master the bike, though, you find the things that take mastering work to your advantage.
The Silvio is still pretty new and exotic, if you will. There are very few around, so bag manufacturers have not jumped on the fast track to make bags that are compatible. A few Silvio riders have added Old Man Mountain front racks to the back of the Silvio and used panniers. This seems to be an adequate workaround. What I think holds a lot of promise is a post not too long ago on the BROL board. The folks at Terracycle are doing some mods to their Double Century bag to make it work better on Cruzbikes. Defjack has modified and permanently attached a similar bag from Radical that looks pretty good. I wouldn't mind seeing if the bag could be modified and remain an easy on and easy off solution, because it sure looks good on the bike.
As far as distance goes, I've only done a few centuries on my Silvio and plan to do some double centuries next spring. The centuries I've done have been comfortable and fast; some of the fastest centuries I've done, in fact. I believe the bike is definitely all day comfortabe and worth every penny.
My feeling is, though, you're looking for an off the shelf bike with all the off the shelf accessories you need to do brevets. While this bike would certainly be capable, it's difinitely not an off the shelf, cookie-cutter bike. You will have to re-learn body english and become creative in making/customizing your own accessories. If you had the time, patience and inclination to do so, I believe you would be well pleased with the Silvio.
Mark