Battle Simulator?

[tadkins]

Think something like this could exist/already exists?

Two gnomes come up with a crazy creation; a pocket dimension of sorts where adventurers and other fighting types can test themselves against carefully crafted, quasi-real illusionary monsters in simulated battle. By undertaking a grand mission to gather data on all sorts of creatures and beings throughout the worlds and planes, as well as hiring multiple groups of adventurers to assist them, people who use their creation and fight simulated versions of all sorts of things. Going to the Abyss? Load up the demon data and test your tactics against illusory demons. Want to relive your battle against that lich lord you fought years ago? The crystals that power the machine can actually tap into your mind for the necessary data, at which point you merely need to step in and fight a reconstructed version of the lich.

The idea is heavily inspired by the KH2 data battles.

[tadkins]

Heh, I guess this idea's a bit too much?

[Uncle Pine]

As always, every problem is easily solved with massive application of Simulacrum, Ice Assassin and/or Mindrape.

EDIT: On a lesser extent, Summon Monster/Nature's Ally should work pretty well. Dragon #302 has rules to expand Summon Monster's and Summon Nature's Ally's lists to ensure plenty of variability. The Halaster's Fetch line creates real creatures from the Summon Monster line that continue to exists after the spell duration expired.

EDIT_2: I completely agree with JDL below. Beware actually using a battle simulator of this sort in a real campaign as it's a really bad idea. But hey, it's doable by RAW.

[JDL]

I'm sure something like this monster grinder would have been invented by some DM in a campaign somewhere, though I doubt it's going to feature in any printed campaign setting.

Why? Ultimately D&D is about adventure and heroics. What is heroic about fighting fake monsters in a box all day? Where's the adventure? Also, where's the loot?

I'd much rather play a real campaign than have my hero spend his time levelling up inside a machine. On the meta level it reeks of a DM that can't be bothered to write a real adventure and prefers to just have his players fight his blocks of stats with their blocks of stats.

[Stegyre]

It sounds to me more like the X-Men's Danger Room or the Enterprise Holodeck, both places that, notwithstanding their supposedly-controlled environment, occasionally get out of hand and can, indeed, provide some excitement and adventure.

An entire campaign should probably not be based around such a concept, but it may certainly have a place within a campaign. I have considered a much simpler concept (Summon Monster traps) as a good -- nigh-essential -- component of any combat training academy.

[Brookshw]

Astral projection traps. Probably could do something with shadowcast illusions