With some of the hybrids that are available I believe they have been crossed with something other than other adeniums.

Oh and I've tried hand pollinating from a dbl red oleander to one of my adeniums. Only attempted once

Interesting.

On the subject of hybrids, I'm pretty sure they haven't managed to get a cross outside the genus or we would have heard something. It's incredibly rare to make a cross between plants of a separate genus, and any nursery that had managed it would be making a huge deal of it. As the odds of success are incredibly low, must nurseries don't have the inclination to try something unlikely to result in success.

One species might be a more viable seed mother than the other. Treating the pollen by microwaving it (it's been used to overcome self-sterility in certain species) or with certain chemicals might also produce effects.

Inter-generic hybrids are common and easy in crassulaceae

I lost concentration after the words in the first conversation(for those) dose that mean common pink will be no more (:

Yeah, Todd, but it really varies from genus to genus. For example, a lot of the hibiscus species aren't even compatible with fellow members of the genus, much less one outside of the genus. To be fair, I think that has something to do with the tropical ones and the hardy ones being from different continents (although even some of the american species aren't always compatible with one another).

So this one could work, because it doesn't have the chromosome problem (part of the reason those hibiscus are basically incompatible barring freak one in a million crosses between the two "right" plants at the right time).

Ah, basically it would mean that you could have cold-hardy-ish Adeniums. You might be able to move their range up a zone or two.

The flowers probably would vary a lot between hybrids, but you probably could get some pretty interesting colors. Adeniums easily have more intresting patterns and colors than both Plumeria and Oleander, so you might see some Oleander-like hybrids with interesting flowers.

We would probably be stuck with the common pinks (ugg), although we'd probably get clusters like the oleanders, and the flower shape might be a bit different.