Well to start it is a wide open field right now as you said. Many of the species have yet to be consistently breed together and most do not have much of any record kept on them for future reference other then perhaps the breeders own. This is one of the things that HBA hopes to accomplish with a long run of public data collection and photo history from various breeders and interested herpers from around the world.
One of the other things HBA is interested in is Conservation through eventual breeding of domestic cultivars that would not be available for collection from the wild. In doing so we hope that we can remove some of the demand for WC specimens so that herpetologists can focus more on ecology based conservation efforts.
We also feel the domestication of hybrids might also help to provide healthier animals that deal with the everyday stresses of captivity and cope with a wider range of husbandry styles. Too many reptiles simply can not cope with the conditions they are handed in the pet trade and this could go a long way in helping to end that problem as well.
To try to answer some of your questions there's no way I'm going to be able to answer them all so I'll just focus on the ratsnakes.
Arizona eligans
Pantherophis Obsoleta
Pantherophis vulpinus
Pantherophis Guttata
Pituophis melanoleucus
Pituophis deppei
Bogertophis rosalaie
Bogertophis Subocularis
Lampropeltis ruthveli
Lampropeltis getula
Pseudelaphe flavirufa
Senticolis Triaspis
All of those north American snakes have been studied using molecular systematics and are now believed to have diverged from the same branch of Elaphe. Due to this common ancestry and all of them having 36 chromosomes they have both a high likelihood of producing viable offspring with a high percentage of fertility. This probability though is diminished depending on the amount of genetic drift that each species might have accumulated since their divergence.
Due to the proven viable and fertility offspring between these Sp. groups: Lampropeltis ruthveli, Lampropeltis getula, Pantherophis Guttata, Pituophis melanoleucus, Pantherophis Obsoleta, Pantherophis Guttata. Which makes up about half of the complex from that branch. I would guestimate that if fertility is proven between any of them and say Senticolis Triaspis which is beleived to be the furthest divergent Sp. in the overall evolutionary complex of this particular Elaphe branch then you would be more likely too also have viable offspring with some of the euro-asian Elaphe branches provided that there aren't any major pre or postzygotic barriers that have developed since their divergence.
To my knowledge there hasn't been any attempts to date between the new-world and old-world ratsnakes or related species. However HBA is still young and hasn't yet reached out to every breeder working with hybrids.
To answer your question about:
9) Lampropeltis t. elapisodes to any other Lampropeltis t. ssp?
Intra-specific hybrids A.k.a intergrades are the most commonly found hybrids in the wild more than likely if someone hasn't breed these in captivity there could be record of them within a specimen collection at a university. I would check the web for these as you can more than likely find at least some trace of them provide there are hybrid zones that exist with any two ssp. in them.
Hope that helps a little.
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Adam
Hybrid Breeders Association
