I've also added three new armor abilities for the armiger:
Three additional armor abilities are added: Instant Fortress, Unassailable Bastion, and Unstoppable Juggernaut. To activate Instant Fortress ability you spend 4 armor tokens as a free action to gain instant access to the defense challenge’s benefit instead of waiting for one round, for a number of rounds equal to your Constitution modifier (min 1 round). With Unassailable Bastion, you need to spend 4 armor tokens as a free action to gain double the benefit of Defensive Roll defense challenges (and its improved versions) as long as you do not move, for a number of rounds equal to your Constitution modifier (min 1 round). Unassailable Bastion does not stack with Sentinel’s Defense. The Unstoppable Juggernaut is activated with 4 armor tokens as a free action and as long as you have moved 10 ft. or more that round, you gain +4 size bonus to all your checks (bull rush, grapple, overrun, sunder, etc), your base defense bonus becomes a passive defense bonus instead, you gain maximum result of your damage reduction roll, and gain an enhancement bonus of +10 ft. to speed during this round.
I am a little worried that Unstoppable Juggernaut may be somewhat overpowered when used with Sentinel's Defense. But time will tell.
[edited the Unstoppable Juggernaut ability...upon reflection it did not seemed unstoppable enough. Heh.]