Hi KsPer,
Cardboards offer the best warranty in the business. 3 years against breakage on Tempo, PRO, FR and Wave.
They are about to release the 2012's and a new model. I spoke to Dan at length recently and he was really frothing over the new models. The FR returns, the Tempo is back and the model that fits in between them, the FX.
I've never had a warranty questioned and these were only from a small run where there was a a few boards that had delam issues due to a new method of bonding the ABS (which was less than successful). Outside of those few boards, we haven't had a single board broken or come back for warranty.
North this year are also offering an additional 6 months on top of the standard 12 months warranty. This applies only to original purchaser and must go back to the shop where purchased to take advantage of the additional 6 months. We had no North twin tips back for warranty last year and only one from a previous year where a customer damaged the board by dropping it on the rail and the top sheet started to delam. Unbelievably, North replaced it with a new Select.

To my knowledge, no second hand board is covered by manufacturers warranty, it only applies to original purchaser.
DM