Hi Ivan,
I am just going down the route of some more exotic training myself, so I might be able to you give you my point of view. I am sure the people who have completed the kind of training, and more importantly have obtained the experience, I am talking about will be along shortly to set me straight.
From reading the reports on the Clipper, I gather that the depths are quite suitable to do on normal gasses (PADI EANx or something like that), so the kind of training you’d be looking for is more focused towards dealing with overheads. Although some agencies offer specific wreck training (and there
are some differences with cave training), it is a bit more common to do cave training for this (just because there seem to be more cave instructors around than wreck instructors, especially around Florida

. Some form of extended range training is not bad either, although this might be as simple as getting used to diving with a twinset and possibly a stage, so you can carry enough gas for a long dive. The penetration training would consist mostly of line drills, team communication and zero-vis training so that is something you want formal instruction in and that intro to cave courses cover well.
The Oriskany with the flight deck at 135’ and the bottom at 212’ is quite a different animal. Although for some people these depths are acceptable on “deep airâ€Â, if you want to actually remember the dive, I’d suggest you need at least an entry trimix qualification by an agency of your flavour. This would entail something like TDI Normoxic Trimix, which only has advanced nitrox and decompression procedures as prerequisites. Although if you're going that way, yuo might as well get teh whole enchilada and get full trimix qualified IMO. On top of that, inside the hangars you’ll have to be completely comfortable with scooters to enable such a dive, so some kind of a more fomal extended range course is also a necessity IMO.
In summary, my take on wreck training goes along two lines: get overhead training (cave) and get depth training (trimix) appropriate for the depths you think of tackling. Although I have no intention myself of diving caves this means I will obtain cave training at some point and at the moment I am working on trimix training (for me the easier part here in the UK). TDI and IANTD are the common choices in the States to do this kind of training (and they even offer specific wreck training through some instructors). Personally I have chosen another agency and my own long term goals are GUE Tech 2 & Cave 1, as that covers almost all the wrecks I can think of that I would ever want to dive. (and I get to drink Kool-Aid in large quantities). Some good write-ups on depth training by other people on this board
here and
here
Hmm, reading back over this, I realise that I assumed silently that PADI Rescue or SSI Stress& Rescue or similar is a given (this is IMO a minimum qualification for this type of dives and effectively what we expect of people to have or reach pretty quickly here in the UK for any kind of diving – although that provokes a whole other discussion).
Oooh, last remark, if you’re looking for an instructor, there is a thread on here somewhere (by Chunky I think) that gives good tips on how to decide you found a good one (normally the quality of the instructor is more important than the letter soup). Can’t quite find it at the moment, so you’ll have to nose around a bit.
Cheers,
Peter