I think a Mage with a necro would be very deadly, mages can summon anything you need ex: stacks of food and water, bandages, pet toys, mana press items(reduce casting cost)items that increase dot spell dmg.
I have a 68 beast that duoed with a necro and they team was awsome. My beast has duoed with a mage as well and it was awsome too.
Best thing to do is sit down study the toons abilities and go from there, but imo it would be a mage with a necro:)

I strongly suggest a BeastLord. The Bst and necro combo seem unstoppable. I play Risingmyst a lvl 51 necro on the Prexus server. If you like make a toon and just observer us as my Beast friend and I play. I'll buy you invise potions or just make a toon with the hide skill. Now here's my reasoning. Though Necros can group well with any class for solo. The Beast has the Bst crack which stacks with the necro conversion..helps with mana regen and hp regen. Necros are not bad healers properly played. I would sugest the Iksar Necro. Though the Dark Elf Necro is not bad ( hide skill can be useful). Anyway,
the Bst and Necro pets are awesome together. My Necro snares dots and heals as needed as well as twich. The Bst slows and nukes as needed. Also Bst can heal pet well and also buff the necro Pet. Also consider this. Both are very good solo classes.
With the bst if your a Dark Elf you can always Hide (like an invis) and sit and med if need be in peace. Though if your friend is going to try the healing route yes, this can be done though theres a trick to it. If you are willing and have not made thy toon yet try prexus. I'll help you get started if you like and teach your necro friend some tricks I've learned. Or just give me a tell and I'll explain as best I can. Though some things may be easier to show by example. In many zones when I'm grouped with mt Bst friend we can act independatly of each other and really rack up AA's or Loot, depends on the zone. Shammy would be a good combo as well as the mage or druid. I've at times grouped with warriors and have been able to keep them healed as I dot, nuked and taped ( depends on situation). Have your necro friend invest if possible in the Abrogation robe. Many Necros over look it. It's the regen +2 that really helps. Also the necro heal Dark Pact is very much in line with a Cleric
s heal at lower lvls. Theres alot I can shre. yet I can be long winded. What ever you both decide on know that I wish thee luck in thy endeavors. May thy Mobbies ever fall and thy exp be everflowing.

You're thinking too far ahead. There would be a good 2 months of playing before they got that far.

Let me put it this way. I am a necro, my dad is a mage, we can kill anything we want by ourself for the mostpart, but we also know our zones ver well. the dots + the big nukes and then the pets dps makes a very deadly duo. and OMG having the mage for the pet toys makes up for not having the beast for buffs. and the focus items are the bomb. as far as race goes, pick what you like to look at cause your gonna be looking at it for the rest of your life in norrath, me and my dad went with DE (hide skill is very nice).

I have a 14 necro that I duo with a mage friend of mine all the time. It's cool because you can really notice the DPS increase with a mage around. We did this all pet-classe group one time in Kurns Tower and we just dominated.

A necro duo's well with most classes. If you want to play a caster they try a Druid. They duo very well with necro's. I should konw, my bro and I duo'd for over 45 levels...untill he learned how to quad kite well. Which is something you can duo pretty good also, with the necro just medding and twiching the druid every time to gets oom or finishes a quad.

Well from personal experience mage / necro combo is very nice in upper level zones like MPG, mobs hitting for 1k ish and i can duo them with a mage friend with ease, go mage baby : P