What about something like Lucius's spells? In my versions thereof:
Hammer of Thor CrAu(Re) 40 (Base 5, +4 unnatural, +2 sun, +1 Re): enchant a metal weapon, covering it with lightning. The weapon deals +30 damage with every hit. (The Rego requisite prevents harm to the wielder.)
Sphere of Airy Protection
MuAuAq 25 (Base 10, +1 touch, +1 diameter, +1 part, free requisite)
The air around within 50 paces of you acquires the viscosity of a thick liquid. You appear to be at the center of a honey-color tainted somewhat translucent sphere. You and anyone standing near the center of the area enjoy a +25 to Soak against ranged weapons fired from outside the sphere, and melee attacks against you are at a -2 Attack and -3 Damage penalty. Movement through the transformed air is difficult, fast (walking-speed) movement requiring an EF 12 Strength check. Long efforts (such as swinging melee weapons or moving for more than a round or two) will require exertion (Fatigue loss). The SG should decide what penalties and costs apply on a case-by-case basis.
Clouds Castle
MuAuTe25 (Touch, Moon, Individual, Base 5)
Changes a normal cloud to an unnatural substance with the rigidity of wood or ice. It can be shaped with carpentry or similar tools. The cloud still floats on the winds just like a normal cloud, but its newfound regidity holds it from dispersing. It can carry a great weight, as much as 10,000 pounds for a large cloud.
Call the Lightning Army
ReAu 45 (Base 15, +2 sun, +1 touch, +2 group, +1 control spirit)
This spell summons 10 jahn, arab air elementals and warriors composed of lightning and whirlwhind. They have Magic Might 10. They will obey the magus for hte duration of the spell or their destruction, at which point they dissipate into thin air.
God of Thunder MuReCoAu45 (Base 30, Personal, Individual, Sun, +1 Rego req)
This powerful spell turns the caster into pure lightning. He can switch back and forth between lightning and human forms by concentrating for a round. As lightning, he is immune to most physical harm but subject to Auram spells. He can travel at great speed, by moving to and from clouds or crawling upon the ground. His mere touch causes great damage to any physical object or being, causing +30 damage per round.
Items carried by the caster are not transformed. The caster cannot use words or gestures while in lightning form.
None precisely 7th magnitude, and most requiring requisites the magus may not have. But perhaps it will give someone ideas. Definitely some interesting things to do with Auram magic.
There are also some fairly high-level spells in the spells wiki, but nothing that seems more appropriate (without knowing the magus).