I've been working on a Monk build for quite a while now. Can't seem to get it to a point where I think it can compete with well played Tier 3's at high levels.
Monk 7/Duskblade 3/Suel Arcanamach 10 makes a decent gish, but it doesn't get Greater Mighty Wallop until far too late, and it relies on all six stats.
Monk 7/War Mind/Fist of Zuoken makes a decent psi gish, but why not Tashalatora?
Monk 7/Rogue 2/Assassin 1/Ninja of the Crescent Moon would make a good stealther, and can use Assassin wands.
Monk 7/Incarnate 1/Totemist 2/Umbral Disciple 10 could be fun, and goes well with the shadowy theme of Invisible Fist/Dark Moon Disciple.
Monk 7/Master Thrower 5/Ninja of the Crescent Moon 8 could make a good stealthy thrower.
All of those builds are decent, but they don't have the damage output that they need. They are pretty good at stealth, especially with Darkstalker and a Ring of Darkhidden and some way to count as standing in less than full daylight, but stealth doesn't kill people.
The trick with monks is to spread your stats around (keeping Str at a 16 or so), and buy stat boosters for everything. MAD is actually kind of a blessing for them, because it means better returns on a smaller investment due to the way stat boosters increase in price exponentially. Unarmed Strikes are also the cheapest weapons to enchant, because so many things apply. You can get an Amulet of Mighty Fists, a Ward Cestus, and those bracers from Magic of Faerun, and they all stack to make your fists the equivalent of +30 weapons.
Good monk ACFs:
Invisible Fist (EoE) - trade Evasion for Invisibility, 1/3 rounds, trade Improved Evasion for Blink 1/3 rounds, both immediate actions
Dark Moon Disciple (CoV Web Enhancement) - trade Still Mind for Darkvision @ lvl 3, trade Wholeness of Body for total concealment in < full daylight @ lvl 7
Holy Strike (CC) - trade Ki Strike (magic) for evil aligned attacks and +1d6 vs good
Wallwalker (DS) - trade Slow Fall for ability to run on walls an equal distance