I think http://www.3rdedition.org/forum/viewtopic.php?t=6598, redesigned for ECL 20, is more along the lines of what people would consider ridiculous. That one requires books like the Spell Compendium and Frostburn which you haven’t listed, so if certain powerful spells aren’t available then you’re fairly limited on how ridiculous a spellcaster can be in comparison to other builds. Probably the most ridiculous melee build I can think of is centered around a weapon from Frostburn and a spell from SC as well, making that too unavailable. You also don’t have the PHB2 listed, which would have opened up many more superb options. If you’re going to make some sort of Mystic Theurge, go with Wizard 10/ Ur-Priest 2/ Mystic Theurge 8 and be sure to get Divine Metamagic: Persistent with a boatload of Night Sticks (LM).
You have the Dragonlance campaign setting listed, so I’d say one of the most ridiculous things you could use would be the White Dragonspawn template. That would mean making a Sorcerer-based build, but luckily I happen to have one that I think you’d like. In Dragon 314 page 36 you’ll find the Master of the East Wind PrC. The build goes Monk 1/ Sorcerer 4/ Enlightened Fist 5/ Master of the East Wind 10, which ends up with 16th level Monk abilities not counting a Monk’s Belt and 18th level Sorcerer spellcasting. White Dragonspawn’s +1 LA would leave you with one fewer MotEW level, which is definitely worth it. Feats should go Stunning Fist (Monk 1), Combat Casting (1), Power Attack (human), Draconic Heritage (gold or red) (3), Ascetic Mage (6), Draconic Breath (9), Arcane Strike(12), Extend Spell (15), and Persistent Spell (18). Don’t worry too much about Int or Wis, your highest stats should go Cha, Str, Con, and Dex in that order.
Use Persistent with Shield, Wraithstrike (CV), Bladeweave (CV), Displacement, and maybe a few other choice low-level spells. Be sure you have Blinding Breath (Draco) as a spell known to use with your Draconic Breath, it even works on constructs and undead because a breath attack is a supernatural ability and ignores magic immunity, while Draconic Breath is a personal-ranged transmutation which affects only your breath weapon. Use mid-level spell slots to Arcane Strike with Power Attack on full attacks, Wraithstrike will make you ignore most of their AC so you should hit every time. Most of your spells known will be for solving problems that your melee and breath weapon abilities cannot solve, such as divinations, teleportations, Dispels, and maybe a few extremely useful offensive spells, plus some buffing spells like Haste, Greater Mage Armor, and Greater Magic Weapon, plus protection spells like Mind Blank. A few good offensive spell choices would be Orb of Acid, Disintegrate, and Mordenkainen’s Disjunction (used to dispel opponents’ buffing spells revealed by Permanencied Arcane Sight).
Get a Ring of Arcane Might (CA) with the effects of an Orange Prism Ioun Stone added to it, the price of the stone should be halved (no item spot cost is x2, so going from no item spot to taking a ring spot is halved) and then increased by 50% for multiple different effects on one item, for 42,500 gp. Everyone in your group would do well to get a Belt of Magnificense +6 (MinisHB), as for only 200,000 gp a +6 to all stats is much better than buying the individual items at 36,000 gp apiece. Instead of getting a Monk’s Belt get a set of Monk’s Bracers, which would be the same thing only made to take a different item spot at no additional cost. A Necklace of Adaptation and a Ring of Sustenance each with the price doubled to not take an item spot is also a superb choice. Get a Ring of Protection +5 with the effects of a Ring of Freedom of Movement added at +50% cost, so it would be 110,000 gp. Get an Amulet of Natural Armor +5 with the effects of an Amulet of Mighty Fists +1 applied so you’ll still overcome DR/magic if your Greater Magic Weapon spells get dispelled, it should cost 59,000 gp. There are also a few Psionic items you should definitely have, such as a Third Eye: Sense and Boots of Temporal Acceleration (with the price multiplied by the number of uses/day you want). Don’t forget about a Cloak of Resistance, and be sure to get a Gemstone of Heavy Fortification (DCN p83). A Pectoral of Maneuverability (DCN) would also be a good item to have.
If this isn’t to your liking, I know of a few other fairly ridiculous builds I think you’d like.