They were expensive though, sometimes selling for twice what Colts were were selling for at the same time. There aren't many, they are all collectable, and the number that were chambered in .38 Super is very low.
I don't know what the price would be for a 1980s era Detonics 1911 in .38 Super. I couldn't find one for sale. They are discussed in forums. People claim to have seen them. Apparently they are passed between collectors like pieces of the True Cross. Detonics fans have a quest to own them all. Here, in his own words, is what one collector had to say:
The link has more pictures and some discussion of variations, British proof marked Detonics, Detonics with no sights, and more. An interesting grail gun, rare, desired, and unusual.