+7 Cover bonus to Ac.
~cost: similar to deflection bonus, so we'll use that: 7^2 = 49 x 2,000 = 98,000
+4 Cover bonus to Reflex saves.
~cost: more useful than "Save Bonus(limited)", but less so than full Resistance bonus, so we'll say bonus^2x500: 4^2 = 16 x 500 = 8,000 x 110% (additional effect in a slotted item) = 8,800.
Immune to Magic Missles.
~cost: similar to a Brooch of Shielding, but it doens't have a limit to the ammound of MM damage it can absorb, but only protects vs 1/2 the battlefield. Rough estimate, 3000g. x110% for additional effect in a slotted item =3,300.
Rough running total: 110,100gp market cost. This assumes that it takes up a limited item space,.. a necklace for example. If you make it not take up a limited item space it'll run you 218,000 - you save 1,100 on the Ref save and MM immunity, but the whole shebang gets doubled in price. If you limited the item to Wizard (or Sorcerer) Only, it'll cost 77,070(slotted) or 152,600(not) respectivly.
That's market cost. Creation costs would be:
Anyone:
~55,050gp / 4,404xp (slotted)
~109,000gp / 8,720xp (non-slotted)
Wiz or Sorc Only:
~38,535gp / 3,083xp (slotted)
~76,3000gp / 6,104 (non-slotted)
And all that assumes your GM would give you the thumbs up to make the item in the first place.
Which most wouldn't. Permanant shielding items really tend to screw things up bigtime.