Yes, there's a "lich lord" guide in the stickies. It's a necromancer focused on skeleton mages. But you need enigma though. Without enigma, it isn't viable. With enigma, it probably is. If you don't think you can get enigma, make another kind of necro.
As any necro with good merc and corpse explosion is hell viable, so hell is quite easy with mages. You just need tank/tanks for them. Attract is best curse to use with mages, works so nicely
I have made one with mages and those can solo hell baal, running from town and killing all along the way quite fast. Wide open corridors there, so perfect for mages. Baal is better target than diablo for magebuild.
I went this way while building one. As mages took only 41 points and get killed easily I needed tank. I choose glay colem, couple of points there and gumpy can tank almost anything. Attract curse is your another tank, pick one monster as target. With those two tanks, you mages are safe.
Lower resist curse is your main curse, so couple of points there.
With some points in corpse explosion and 1 in revives, you can solo hell baal quite easily. Just avoid narrow areas, pits and ancient tunnel are two open areas (tc85) where you can lvl, in baalrun you need resist, but just lightining, so its easy to get.
I picked rogue merc with harmony, that vigor aura is so good with mages, they need to get in firing position fast, and that glay runs so fast to tank.
And lower resist curse works nicely with harmony bow, easy to get first corpses. Threachery armor and life leech helmet. Iron maiden etc. don't kill mages while running baal, so its perfect choice for there.
Of course infy, enigma are very nice for this build, but only needed if you do full hell games.
With act1 merc and mages, bosses are hard. Urdars revives or going melee route with necro. Or give edge bow for rogue.
And gear, mages as high as possible. Around 30 they are hell baal viable, around 40 those kills fast and 45...50 godly.
Nmare is easier/as easy with mages than with skeletons, so you fly through that if decent skill lvl.
Great answers, cheers guys.
I'm a poor player, tend not to get characters particularly high level or gear. Currently got a vanilla skellimancer/fishymancer, second I've had, good fun.
Think I'll go a simple route. 20RSM, 20 SM, 20LR, 1pt most everything else. Use golems / revives as tanks. Harmony word sounds great, the main issue with mages is them wandering around doing nothing, I find. Couple other things for the rogue and resist/+skills gears for myself, maybe a runeword with an aura of some sort if at all possible. Is a second aura-item such as something with Conviction or Holy Freeze a good idea?
You probably don't need 20 LR, it has diminishing returns and one or a few points +skills is enough. Holy freeze on merc + clay golem will greatly slow everything down and give mages more hits. Conviction on merc is obviously awesome for mages, but requires the expensive Infinity runeword. If you can't afford it, Harmony on an act 2 NM def merc (HF) should work well.
I ran my own "Lich Lord" with out an Enigma and I used Town Portal scrolls in key areas to both collect my army and focus them. I managed to get an amulet with Teleport charges on it and the Teleport blew the TP away but TP is great for people who don't have some means of Teleporting or can't affort to recharge items with Teleport. Enigma is great because the Teleport only drains Mana.