There were several different custom pistols based on Colt Trooper Mark V and King Cobra revolvers.
Most of these were produced for Lew Horton Distributing company.
Horton has offered limited production pistols for some years. Lately they're mostly S&W guns, but the earlier models were mostly Colt's.
The Boa is a much sought after model, based on Colt's Trooper Mark "V" revolver, which is the direct predecessor of the King Cobra.
The Boa was basically a Trooper Mark V, with a Python-grade Royal blue finish and a Python barrel.
These were available in 4" and 6" models. There were apparently 600 guns produced in 1985.
It's believed that Colt patterned the later King Cobra after the Boa.
Again, the Boa was produced exclusively for Lew Horton, and bring high prices from collectors, due to the low production.
In 1969 Colt introduced the first in a series of new type revolvers to replace the older Colt's which were simply too expensive to continue to produce.
These revolvers all used very similar transfer bar actions.
The series included:
The Trooper Mark III series.
The Trooper Mark V.
The King Cobra.
These revolvers are some of the strongest and most durable revolvers ever made.
Master gunsmith Jerry Kuhnhausen believed these later Colt revolvers were the strongest mid-frame revolvers ever built.
He attributed the strength and durability to Colt superior forged frames, and the high quality heat treating of the frames and cylinders.
Other than buying a very expensive collectible Boa, the nearest option is to buy a King Cobra, which was available in stainless and in blued steel.