"frozen" minecraft items

You can have an unpickupable (that's not a word) item by using the PickupDelay tag.

/summon ~ ~ ~ Item {Item:{id:#,Damage:#,Count:#,tag:{###}}, PickupDelay: #}

Replace the '#' with the correct values.

To make it immobile (static in space), you don't use the NoAI tag as it does not have any AI (unlike mobs/creatures). All it does is make it immobile (until you break the block under it to make it fall or push it). Instead, you can:

• Use the NoGravity tag. (Though it'll still have its bobbing effect)
• Attach it to an invisible armor stand and reorient the hands to be facing straight ahead (parallel to the ground).