Solo?
Pick another class..
If set on solo'ing a monk, avoid Dragon
Honestly, don't play the Monk with visions of mowing down badguys before they can hit back.. and expect to hit a cap on how far you can get solo.  I'd very seriously suggest you try another class for solo.  Likely a caster type.  That's what Sony preferences, casters... the rest is afterthought to keep casters alive in heavy content areas.

I've been experimenting with a monk solo build. Please comment what you think.

Race: Orc (the racial ability is essentially a full heal/second life)
Style: Harmonious ( for defensive stance/diamond skin + dmg reducing debuffs)
Active abilities: Aum Ti, Secret of Ice, Defensive stance, Iron Hand. (Optional/circumstancial: RiTw, Find the Centre, Swaying Step, Iron Skin, Ignore Pain)
Gear; Martial Sword (nice parry to proc -50%dmg debuff)
         Crafted +evasion gear, always Qalian style (self heal proc)
         3 or 4 Pariah's Boon of Health items (boon of health stacks with qalian self heal proc for some impressive self heals)
         A few pieces of +mitigation gear/jewellery wouldn't hurt either.

(To be specific i use the Lord's Sword of Unity, all T5 Flawless crafted gear, and the "tank" set of lucent jewellery.
Melee evasion sits at around 60%, and melee mit about 25%. Heal procs EVERY attack for 60 hp.)

I was dragon until lvl 50, and remember the long down-times (waiting for hp to regen/cooldowns to end) when trying to farm 3-dots for instance. While i'm not sure such a defensive build is achievable at lower levels...i think something along these lines may increase the speed of solo xping.
I originally made this build for pulling in Apw, but tested it in Thelaseen while farming for Motes of Ancient Power and found i could solo tank 4x 4dots there comfortably!
The other night in a crypt group at Ikwazon the dread knight had to leave so i thought i'd have a shot as MT i killed all the 4 lucents at the crypt entrance area so i could use AoEs, then just tanked each wave by spamming Whirling Storm and/or AoE finisher chain. Not saying it's possible to solo all 3 at once , i had some nice buffs and 2 healers on my back, but my HP went down much less than any plate-tanker and held aggro on all 3 at all times. Get the gear i have and try a lvl 50 4dot in flordiel for instance. It put a whole new perspective on monks for me.

You can make some useful macros involving /wear ... /combatformset ... to quickly switch between defensive and offensive gear set-ups.
I hope this helps you with your decision Zealots.

As to the ideal build, I'm sitting at about 28% mitigation as an Orc Dragon in Stone Dragon stance, and my gear isn't even that great. Hell, I don't even have any lucent jewelry yet but the Warrior rank necklace. I'd also doubt the value of evasion, since it only seems to work half the time.

And Maciver, it does get harder the higher in level you become. Maybe the effect is less noticeable since you started after GU 3.2? I know I had huge problems taking on even con 3-dots at level 50, even when using my self heal and racial I would have about a 40% success rate. Then again, I'm a Dragon, possibly the worst solo-wise of any class. It's better now - I can manage to take down a 40 4-dot without using my self heal if I'm lucky, and about a 51-52 3-dot now.

15 and anything but Dragon 

I play a harmonious monk, I started as a Drunken, but by lvl 17 I switched-pre revamp harmonious was easier to solo with, post revamp its even better.  Solong lizards for hunters League quest was doable, I was a few lvls higher but I could take on 2 3 dot mobs at the same time, though left low health.
I went Kojani human monk and the 45% heal does help, though I should have gone Qalian for the 10 seconds immunity

Lvl 22 with a yellow weapon and solo very very well.