One of the key ideas behind the 3x version of Midrea is that like some of the old school games (think Expedition to the Barrier Peaks , The Sheen Invasion from 2e and even as far back as Blackmoor) almost anything goes in Midrea.
I can fit in almost any concept without making the game world too absurd. The only rules are
#1 The players have to all agree to that level of Wahoo
#2 Don't make anything that would offend others
#3 and last: The game has to be high enough level
Let me show you some examples, 6 new players, 6th level game each with a wild concept..
#1 Concept: A Paladin based on that Chick from the Heavy Metal movie only a Dude
Solution: A Paladin with the Shining Knight option. Spend 5th level feat to treat mount as a Pegasus. Make magic items look cool
#2 Concept: A Combat Robot from another time with integral blaster and combat software
Solution: Warforged race, Warlock levels to cover integrals and Warblade abilities to cover combat software. Use Martial Study and Extra Invocation where needed to mix.
#3 Concept: A Magical Talking cat
Solution: Create cat racial template off base stats plus awaken spell, give Sorcerer with Dreamspun bloodline levels as Wizard Levels are just too silly. Since cats don't have hands, give said cat equivalent of Vow of Poverty feat. Drop Exalted Feats for a Neck Slot and optionally Bonded Item ability.
#4 Concept: A Time Lost Psychic Super Soldier (probably from the universe the Robot is from)
Solution: Human Psychic Warrior. His "ultra tech" items are just re-skinned wands, magic armor and such. In time as he levels up he can gain new items (repair stuff he already had) or "recharge" new ones as per building new items ...
#5 Concept: The Perfected Flesh Golem
Solution: Warforged with no innate armor, use the Factotum class to represent myriad abilities and powers.
#6 Concept: Zombie Wolverine with necrotic claws .. By now I am probably going Why Me ? but its doable with a bit of effort
Solution: Longclaw Shifter with Necropolitan Template treat as ECL+1 for stat assignment. Use a mix of Barbarian, Dread Necromancer and Rage Mage prestige class tweaked as needed. Allow the Dread Necromancer touch ability to be used with claws.
and viola, with a little re-skinning almost anything can be made
The Return of Planescape? - Curious. There is a brief note on this 'countdown' at Enworld.
13 hours ago