such as giving stats. or do they keep their magic?
There are no Tremere Vampires in ArM5; they were a figment of ArM3's imagination.
well older books are ok too.
Houses of Hermes:True Lineages has the Dhampir, a faerie vampire. These may be Gifted, but due to previous stigma the House (Tremere) do not train them as magi, they would have to be a different House.
I don't think they are in older books either. Just something alluded do. I seen to recal something about Grimgroth and Mistridge, but that is about it and I don't quite remember what it was.
Just use the White Wolf books. Easy enough to convert.....
I think I just threw up in my mouth a little.
uhm do i sense a certain hostility towards whitewolf? 
So much hatred for White Wolf. A shame really, considering that they are how many of us discovered this game.
Nothing against White Wolf here. While Ars Magica and the WoD setting have common ancestry, it's important to note that they are very different settings in many, many ways.
Vampires, as per WoD, don't really easily fit into Mythic Europe. Or more, the do - but they're either a type of faerie or a type of demon, depending on your whim. From a hermetic standpoint, they smell like either free vis or target practice. They definitely don't fit in with the Tremere doctrine; either one sounds like subjugation to a supernatural power in some way or another.
House Tremere themselves have undergone something of a significant rework since the WoD days, while staying true to the core concepts. They're no longer moustache-twirling villains (although individuals certainly can be), and it is very possible to run an extremely heroic, good-aligned game where all the PCs are agents of House Tremere should you want to. Literally charging around the countryside rescuing damsels, saving towns, defeating diabolists, murdering vampires, hunting werewolves and slaying dragons. By the same token, it's equally easy to run a Tremere-as-jackbooted-thugs setting without changing a jot of the ArM5 canon; much like many other large organisations, it's a lot down to the individuals you're dealing with as much as the organisation as a whole.
The new House Tremere has more in common with the oWoD New World Order than it does with the vampire clan.
Though as anyone who games with me knows, I'm not a fan of the Storyteller system. Settings, fine. System... eugh!
As in it's a bit of a stretch to call it a system?
For Ars Magica, no.
But if you really want this, take a look at the old House of Tremere book, for oWoD, Vampire the Dark Ages.
Good luck finding it though.
For me, my first roleplaying game was D&D, then Star Frontiers, and then Werewolf: the Apocalypse. That led me to Mage, which led me to Ars Magica. I guess I'm in the minority that likes the World of Darkness. I confess, I like the dark atmosphere and metaplot of AR3 over the happy-go-lucky atmosphere of AR5. And I still maintain that Mark Rein-Hagen was a genius when he thought of Ars Magica. Sorry I can't help more with the Tremere except to add lookimg into the Transylvania tribunal book for ideas for Vampires. Hermetic Projects also has a section on creating a lich which also might help.
Isn't there one of them in "Triamore: The Covenant at Lucien's Folly"? That's the one where six things that will end the world unless the PCs do something are all within 30 miles of each other, isn't it?
There were Tremere vampires once. They're dead. Basically "Will give soul for power" is not part of the House design anymore.
The book raises the possibility of a Tremere dhampir-mage with the Dark Secret flaw, which sounds pretty fun to me.
Aside from True Lineages, there is a lot of interesting vampire stuff found in Against the Dark-The Transylvanian Tribunal. Lots of cool House Tremere goodies to. And dragons galore!
Well, such a circumstance doesn't fit with the Tremere I see. It would involve a Tremere who has gone rogue, and has high InVoi to open the Arts. It might be he wishes to discover secrets to longer life, and believes this is possible by taking a Dhampir. I wouldn't require the Dark Secret flaw, I'm not a fan of cumpolsory story flaws, but would simply inform the player, that if ever discoverd, the character will be declared Orbus, and may be on the receiving end of 90 or so declarations of Wizards War. It is the one area where I would see it gong to war as a whole.
Story flaws should be chosen if you want that story, Dark Secret means telling stories that center on the character trying to maintain the secre or how they react to the story coming out to different people...
whether or not clan tremere or the new world order are more evil depends on your interpretation.
at it's core the clan tremere in wod is about these:
"presenting a unified front to outsiders,a nice respectable public face(while hiding the nasty parts in the basement), supporting order(one that puts them at the top of course), subty influencing and slowly dominating the vampiric world, very hierarchical , very pragmatic and maybe add a bit of conservatism too
Perhaps the section of interest to the OP is regarding the oppidum (covenant, of sorts) of Laniena in Hungary (Chapter 3). Here, it is mentioned that House Tremere has had issues with vampires in the past. The most recent incursion, about a century ago, followed the same pattern as previous incursions. It all started with a dhampir. These are the children of vampires, and faerie blooded. Upon death they become vampires (i.e. full faeries). A dhampir was trained by a Tremere magus, and subsequently died without anyone knowing. A vampire resulted, who then continued to masquerade as the magus whilst taking other dhampirs as apprentices He trained them as magi, and then killed them to make more vampire magi.
The nest was eventually killed off by a non-Hermetic vampire hunter, who then went on to purge House Tremere from all other vampire magi. A rule was then made that House Tremere will no longer train dhampirs as Hermetic magi. The vampire hunter joined the Order and founded Laniena to train more vampire hunters.
Mark
Would a campaign about Tremere vampires be called the Twilight Saga? 