The "University Hybrids were developed from a cross of cardinale X nudicaule tetraploidized (with colchicine) and then crossed with elatums. Unfortunately, the red genes have been difficult to separate from less desirable characteristics.

Here is a link that might be useful: abstract

Another approach was a hybrid of cardinale with the yellow zalil. Colchicine, again, to double the chromosomes. Crossed with tetraploid garden types gave plants with various gorgeous shades of strawberry pink, orange and various intermediates.

Many years ago I joined the British Delphinium Society in hopes of finding some of these hybrids. The secretaty of the society had never heard of them. Then, by a wonderful coincidence, there was a picture of them in the society's annual that year.

Karl

The 'Red Princess' delphinium was reportedly shown at the International Flower Trade Show in 1997, but I can't find a source for it.

A double red is listed (without picture) on this web page:
http://www.roughamhallnurseries.co.uk/Delphiniums.htm

And Delphinium 'Coral Sunset' is pictured at PlantSpotters, link below.

Karl

Here is a link that might be useful: Coral Sunset