Exactly how do the Rend attacks Frostrager and Feral Template (can't find the link, sorry) stack?

As far as I can tell, if one can make secondary claw attacks after a full attack of unarmed strikes (IMO fairly reasonable), then you get:

1-4 unarmed strikes, more with one-two punch, flurry, snap kick, etc.
1 frostrager rend with 2 or more unarmed hits
2 claw attacks
1 rend with 2 claw hits
2 rakes if pouncing

Also, should natural attacks get the cold damage from Frostrage? I know that by RAW they don't, but RAI (especially the rends)?

I realize that this could become a bit absurd, but is there a good build that could come from it? Savage Grapple abuse from Black Blood Cultist springs to mind.

Does this get too ridiculous too quick? Other thoughts? Opinions? Madness?