I'm looking for a location with a magma pipe and chasm-end of an underground river in close proximity (like in the same 3x3 embark). I'd like the underground river to be long enough that I can get a breeding pair of crocs before they get flushed down the end, even if I have to expand my embark to manage it. HFS not necessary for my needs. The magma pipe doesn't NEED to breach the surface (forces me to quarantine the imps anyway), but it'd be nice. I'd prefer a mostly flat area to work with, and while in no way mandatory, I'd be great if a major rock layer was obsidian. Savagery is unimportant as I can get most dangerous animals from the elves instead of traps, but I'd prefer a neutral alignment. I have no use for non-reproducing skeletal creatures.
Now, I've gotten sites like this fairly readily using worldgen manipulation, but this last part has proven seemingly impossible: I NEED access to bauxite. Doesn't have to be on the map, I'm fine with getting it from traders/embarking with it, but it's NEVER AVAILABLE on the worlds I generate with high volcano activity, and the worlds with low activity never have good sites otherwise. I hate working with magma with no fire-proof mechanisms.
Every other possible feature, I don't need. In fact, I'd prefer to not have them get in the way. I like having my only water source underground, and the only chasm I need for my efforts is the small 5x5 pit at the end of a cave river. I realize it's unlikely that my ridiculously specific demands will be met, but maybe someone here got lucky and found something similar at one point.