Story Idea: Griffin's Eggs

My 4ed saga is set on the border between England and Wales, currently in 1206. The magae have had a couple years without too many outside pressures, and we are in the mood for a story with a little more fantasy to it. So here's my idea:

Scene 1: A forest calamity
Some covenant members are called to investigate a particularly gruesome bandit attack on a small merchant caravan that was traveling down a forest road near the covenant. The magae get involved because one of the wagon bears what appear to be magical symbols. The entire merchant company is dead at the scene, and two of the three horses are gone. The carcass of the third horse is nearby, horribly torn, as if predators have already been there, although the human remains seem to have been left alone. Bits of shell from what looks to be a very large egg might be found amid the wreckage of the magically marked wagon.

Scene 2: The arrest
A few of the covenant's grogs find the remains of a butchered deer in the forest, and are arrested by the local sheriff for poaching the King's deer. This is an offense punishable by hanging, and the magae will need to act quickly to save their grogs. The evidence agaist the group is circumstantial, as the missing deer meat is not found with the group, but the magae will still need to figure out who killed the deer.

Scene 3: The glorious creature
At some point, the griffin responsible for the carnage thus far will appear, either lured by the magae, or just as it is picking up a light snack of horse. I want this scene to be relatively short, without combat, if possible, just to give the magae a glimpse of the majesty of the beast.

Scene 4: Interlude
More deer are found dead, and a group of "foresters" is encountered in the woods. The foresters are in reality a group from a rival covenant attempting to track down the griffin.

Scene 5: The confrontation
The magae track down the griffin to its lair, where there are also two eggs hidden. At the same time, a rival magus appears on the scene. The rival wants the eggs and the griffin. The magae have several options: Leave and let the rival deal with the problem. Help the rival dispatch the griffin and split the vis rewards from the beast and the eggs. Drive off or kill the rival to protect the griffin and the eggs. Drive off or kill the rival in order to reap the vis rewards themselves. (These last two could result in a Wizard's War if the rival is driven off, or in a March if the rival is killed; I do not anticipate my group going for the kill.)

The Background: A magus had earlier visited the Pyrenees, killed a griffin, and made off with her eggs. His plan is to hatch his own flock in the west of Wales and use the beasts to defend Wales against the English. He traveled with the caravan across the English Channel and the across England, but was delayed by rains and an actual bandit attack. None of the caravan was seriously injured in that attack, but it did serve to disrupt one of the protective spells, and forced the magus to use some of the vis he was carrying to protect his cargo. Because of the delay, other protective spells expired, and the low quantity of vis left prevented the magus from renewing all of them. This might not have been a problem, except the griffin's mate, tracking the eggs and murderers, was able to renew the chase with some of the protections gone. The magus, wounded, escaped the encounter and sent a conferate to retrieve the eggs.

I can envision several more stories coming out of this, including one where the PC magae gain custody of one of the eggs, which they think is a vis source, but it actually hatches at some point! Now, they have a baby griffin they can train, if they can find a way to keep it fed. If the parent is kept alive, it can also help launch a few stories.

I have some questions that I would like some help with:

  1. What kinds of spells/items might griffin eggs be used in? Fourth ed has griffin eyes as spell foci for two spells, but I could not find any references to the eggs.
  2. What kinds of protections should be placed on the eggs while in transit? I am thinking of a ReAn version of The Shrouded Glen, as griffins are supposed to be excellent hunters, and a way would be needed to hide from possible pursuit. A moon duration for this spell would be appropriate for the story, and the fact that it is a ritual requires the use of vis in the casting. A moveable ward against griffins would also be in order, as would some preservation spells on the chest prepared to carry the eggs. Anything else?

Thanks for the thoughts on this.

I don't have any comments on the questions posed; however, regarding :

Scene 5 (Confrontation)
This strikes me as a classic opportunity for the use of Certamen. If the PC's don't think of it, then the rival maga would challenge the party's "champion" to Certamen, the winner being the one to claim the egg. You, as storyguide, can set the rival's Certamen ability at whatever level will best provide a fun challenge for the party. And of course, if the parties decide to work together, then all the better... no need for Certamen.

A few other story spinoffs would be:
A) if the PC's gain the eggs, then the original owner could bring up charges of ownership at Tribunal. This would be all the more complicated if Certamen was used with the Owner's agent. Boom! you've got a nice story for the next tribunal, where the players are trying to get votes from other magi in exchange for favors, etc. And do the rival magi hold grudges against the covenant?
B) if the Griffin does hatch, then this could bring unwanted attention to the covenant during the training period.... A wild, young Griffin may not be too keen on the Code, afterall.
C) Once the Griffin gets old enough and wants to mate, you could have some fun....
D) Does one of the magi make the Griffin a familiar?