Can we let summoning skill allow for more than one elemental transformation at a time?

Something like: 250 summoning will get you 2 transformations. 550 will get you 3. 850 will get you four... and so on until you can hold all transformations at 1750. Maybe make it an average of arcana + summoning.

Right now, we only have Aegis of Granite and Mantle of Flames, but the barrier review will also give us stone veins and a liquid body. This would also give some justification for adding transformations to other books. YS could be an air-based transformation that reduced all hindrance in a way that made brig and maybe plate a viable option. Maybe a lightning transformation that surrounded us with bolts of electricity. They would lash out anytime something made it to melee with us (hidden or not) to stun them. An aether transformation that separated our hands from our body, or created a nerveous system of pure aether that infused us periodically with raw mana (think mana regen bracelet, but more powerful), or protected us from attempts to strip our magics.

Either way, we become something more like an Avatar ( http://www.withanaccent.com/wp-content/uploads/2012/07/avatar-aang.jpg ) than a lesser elemental.