Just my two cents as a soloing Mage. My Mage was born on Jan 31 this year. I had about 4 months experience playing EQ a couple years ago, so I was basically a noob 6 weeks ago.
In that time, I have solo'd myself to 55. I haven't tried killing reds since the teens, and I don't really see how it can be effective at high levels. I would have to think that any class that takes melee damage is out, the hits just come to fast and too hard to make it effective. Sure you might take that red down but if you end up with 1% health, 5000hp can take a while to regen :)
I was starting to struggle in my soloing about 10 days ago (around level 50) because mobs started hitting too hard and I wasn't able to keep up with my heals. I started surfing the web and learned how to "Chain Pet". Simply brilliant. In essence (and yes I know this is old hat to most of you), you summon a pet, DS it, and send it end. When it nears death, start summoning another. Rinse and repeat til mob is almost dead. If you choose wimpy mobs that walk at low hp, you can use a clicky focus to reclaim and land a small nuke for full exp.
I've used this to solo in Dulak Harbor for the last 5 levels and I don't think I've ever dropped below 80% mana with nothing but the new mage pet canni spell.
So, for my money, Mages are good to solo. Maybe not the fastest or coolest, but they are very simple to solo and enjoyable at the same time.
*shrug*