I have a 3rd life pure monk, unarmed, and a 1st life 12 monk/6 ranger/2 fighter monkcher, and I'm here to tell you that the DPS isn't even close: Ranged wins, hands down.
I do keep a melee option on my monkcher, but there are a few points to bear in mind:
1. You do not have the AP to both max ranged and all the TWF enhancements; there just aren't enough AP to go around.
2. You DO have the AP to max ranged and get decent staff enhancements.
3. You can save a feat or two by not taking the xTWF line.
4. Sireth is really easy to get...
I stay ranged ~85% of the time, switching to melee to generate ki and/or to fight trash while MS/10k is on cooldown, but it isn't necessary most of the time, and even in elite raids, I have to be careful about when I cut loose or I WILL get aggro, no matter who is tanking. I keep hotbar 1 for ranged and hotbar 2 for melee, so I can switch quickly between sets of abilities.
Soloing a monkcher is the easiest thing in the world; just wait on big fights until MS is off timer, turn IPS and paralyzing on, and clear the room, but then, soloing a pure unarmed monk is pretty sweet, too.
12 fighter will NOT get you more DPS over even 12 monk, unarmed; you can make an argument if you want to TWF with khopesh, maybe, but you are really only upping your critical damage while dropping your base damage, and spending a ton of AP for the privilege. 2 Ranger isn't enough to earn you +10% off-hand proc.
I'm about to reroll my pure monk into 12 monk/4 ranger/4 fighter; 12 monk gives improved evasion, high base unarmed damage, access to monk epic feats, abundant step, and master of forms (you can take grandmaster as a selected feat); 4 ranger gives +10% off-hand proc, Ram's Might (+3 damage per hit), TWF for free, and wand usage; 4 fighter is mostly for feats, to get all of the xTWF line, Dodge/Mobility/Spring Attack, and Power Attack, Cleave, Great Cleave (to open up Overwhelming Critical), but also adds some weapon damage and I'll probably take Contemplation for more passive ki gen. I'm going Half-Elf for the Paladin Dilettante, to add crazy saves into the mix.
If you absolutely want to use khopesh/bastard sword/dwarven axe/whatever other non-monk weapon, 9 monk/8 fighter/3 ranger will still come out ahead of 12 fighter/6 monk/2 ranger, and have better defense, to boot.