Since my initial try at building a Ranger/Heartwarder/Oozemaster didn't work out , here is a clerical version:
Race: Avariel (+4 Dex, +2 Int, +2 Wis, -2 Con)
Starting Stats: Str 14, Dex (8+4=)12, Con (14-2=)12, Int (14+2=)16, Wis (16+2=)18, Cha 10
End Stats: Str 14, Dex 13, Con 12, Int 16, Wis 34, Cha 10
Classes: Cleric 17 / Heartwarder 13 / Ooozemaster 10
Skills (In Game): Animal Empathy 39, Bluff 5, Concentration 44, Heal 55, Lore 46, Persuade 22, Spellcraft 46
Feats: Armor Proficiency(all), Blind-fight, Charisma Increase V (Heartwarder +5 to Cha), Charisma Penalty (Oozemaster -5 to Cha), Disarm (granted by Whip weapon), Dive Attack, Dodge, Epic Toughness I (I had to take something for the 13th Heartwarder level, so I left it to the end and took the extra 20 hitpoints), Exalted Turning, Fey Metamorphosis, Good Domain Powers, Great Fortitude, Great Wisdom VII, Hardiness Vs Enchantments, Heart of Passion, Immunity to Sleep, Indiscernible Anatomy, Keen Sense, Keen Sight, Lips of Rapture, Low-light Vision, Major Ooozy Touch (Black Pudding, Gelatinous Cube), Minor Oozy Touch (Brown Mold, Grey Oooze, Phosphorescent Fungus), Mobility, One With The Ooze, Oozy Glob, Practiced Spellcaster(Cleric), Protection Domain Powers, Shield Proficency, Slime Wave, Spell Focus(Enchantment), Tears of Evergold, Turn Undead, Voice of a Siren, Weapon Proficiency (Elf, Simple, Exotic)
I took the Cleric class up to level 12 before begining to take Heartwarder and Oozemaster in alternating steps. I found that while Ooozemaster is limited to 10 levels, Heartwarder is not, so I took a couple more of those. The 13th level of Heartwarder gives me a choice of three feats, none of which I was particularly interested in, so I returned to Cleric. The 40th level would not give me a feat as a Cleric, so I used it to take the 13th Heartwarder level.
As a cleric, I put skill points into Concentration, Heal, Lore, Persuade (occasionally after I reached 6 ranks), and Spellcraft, plus three cross-class ranks of Bluff. As a Heartwarder, I found I could put points into Animal Empathy, so figured 'Why Not?'. I was surprised that I could also put points into Perform - unless the cleric multiclasses as a Bard, what benefit would the character receive? I left that skill alone. For Oozemaster, I just put skills into Concentration, Lore, and Spellcraft.
Spell casting - this character is capable of casting spells up to level 9, plus epic spells.
With no enhancement, she can cast 6 / 9 / 9 / 9 / 9 / 8 / 7 / 7 / 7 / 6 spells of level 0 / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 respectively.
The Girdle of Holy Might adds one spell slot to levels 5, 6, and 7. The Ring of Holiness adds 1 spell slot to levels 0 through 4. A Peripat of Wisdom +10 increases Wisdom to 44, and the Shield of Prator increases it further to 46 (technically should be 47, but the game limits increases to +12). All together this allows the character to cast:
7 /12 / 12 / 11 / 11 / 11 / 10 / 9 / 8 / 8
On a personal note, until I saw it, I hadn't realized that the GUI would allow more than 9 slots per level! I'd thought the extra slots would be unavailable, so I never tried to gain them - now I'll have look at a really uber caster character! :E
For epic spells, the Gloves of Spellcraft boost Spellcraft by 30 to 76, and the Ring of Spell Battle adds another 10 to take it to 86. With this (and sufficient gold & XP), all Epic Spells can be learned in the Laboratory. For casting, the Lore of 46 only allows 4 epic spell slots, but the Ring of Spell Battle can be replaced with a Ring of Insight to raise Lore to 51 and have 5 spell slots (though the lowered Spellcraft might make casting a couple of them tricky).
The character's caster level (Cleric) is: 17 (base) + 13 (Heartwarder) + 5 (Oozemaster) + 4 (Practiced Spell Caster to make up for some of the Oozemaster reduced casting progression) = 39. The Exalted Turning feat could be switched with one that aids spellcasting (Spell Penetration?) if it is really necessary.
I'm still wondering what happens when a Fey (from Heartwarder level 10) becomes One With The Ooze (Oozemaster level 10)! What does Tears of Evergold look like then, and would anyone dare to to try the Lips of Rapture?!
Incidently, why is Heartwarder able to go beyond level 10 but Oozemaster is not? They both 'end' with a transformation, and usually a 10-level prestige class is allowed to increase once you are an epic character.