OK, time to get serious on this.
I didn't want to flesh in too much of the detail, because I'd like the rest of you to have some chip in here. Bascially I'm thinking a Spring/Summer covenant, with the following, but to be fleshed out with suggestions from the rest of you.
The covenant has existed for ten years, and was originally founded by Petrus of Jerbiton. Petrus has retired to Valnastium, because although he loves the city, he thinks that the best way for him to live, for now, is in a community of his peers. When he left, he allowed the Tribunal to find replecements for him, but had the final veto on any they selected. He has never discussed why he set the covenant in Lubeck, given the difficulties that this naturally causes. Some suggest that it was simply that he found the covenan't vis source and thought this was a perfect opportunity, or perhaps he had another reason that he did not ever discuss.
The covenant, physically, is an imposing set of buildings near the Lubeck docks. The covenant has its own small dockyard, a large warehouse, and Petrus's old house, which is a sprawling mansion supposedly paid for from his life as a mercenary. It also owns many of the little houses and shops that surround its part of the city.
The covenant also extends, beneath the warehouse, through a series of tunnels out along the seabed. The covenant's vis source is found almost a mile from shore, resting in a magical aura where Petrus once also kept his lab. The area is protected by a circular ward that keeps out water, and has minor magical devicies that freshen the air and provide light.
In the centre of the area are the bones of an enormous, armoured fish. The lichen that grows on this fish contains Aquam vis, which the covenant trades at tribunals for vis of other types. The covenant also has two other minor sources of vis.
The sancta of the magi can be in the covenant's buildings, scattered about the town, under the earth or upon the seafloor. The covenant's library is kept in a special room in the tunnel network, in case the mundanes ever attempt to search or ransack the warehouse during times of civil unrest.
Power level: up to 1000 points
Typical income (the covenant has a fishing fleet of minor vessels)
1 lab each
1 grog per magus and 2 servants each, pooled.
Urban -3
Edifice 1: The covenant's odd structure.
Residents: sailors and their families, some shopkeepers and crafters.
Strong Community +1
Guild -1
Hidden Ways +1
Books
Summae 450 points (feedback by players very welcome)
Art Level Quality
Cr 15 15
In 15 15
Mu 15 15
Pe 15 15
Re 15 15
An 15 15
Aq 15 15
Au 15 15
Co 15 15
He 15 15
Ig 15 15
Im 15 15
Me 15 15
Te 15 15
Vi 15 15
Lab Texts 250 levels 50 points (similarly, feedback welcome)
Money 100 pounds 10 points
Vis 30 pawns per year 150 points (feedback...)
250 pawns stored vis 20 points (welcome...)