I've got a Raleigh Olympian road bike I use for commutes and my neck is killing me (congenital problem). So I want to put gull wing cruiser bars on this bike, with mountain bike levers in the center area near the stem, leaving the original brake calipers and tube-mounted shifters in place. I know this sounds ridiculous and I also assume plenty of people will say, "just buy a commuter hybrid", both of which are moot points. Is it possible?
The tricky parts are the size of the center clamp area of the handlebars and the areas where the brake levers clamp to the bars. There are many choices… Older road bikes tend to have a 25.4 mm center area, newer ones may be either 25.4 or 26.0 mm, your stem has to match. Some stems are 26.0 mm with a shim to take them down to 25.4. Brake lever clamp sizes are also different between mountain and road bikes. You'll want to pick your bars and then select brake levers that will fit them.
The other thing you'll need to be aware of is that brake systems have two varieties of "pull" – how much cable movement it takes to actuate the brakes effectively. Caliper brakes like you have, and cantilever brakes (which are common on mountain bikes) use a "short" pull. V-brakes use a "long" pull. It sounds like you need short pull levers. They may also be described as levers for cantilever brakes.
If you like the Albastache bar it has the advantage of being sized to take road levers (23.8 mm diameter where the brake levers clamp on), so you avoid the expense of a new set of levers. It also has the possible downside of a 26.0 mm clamp area, so the money you save on levers may go towards a new stem.
Ditto also makes a bar they call the Albatross which has a similar shape a 25.4 mm stem clamp and takes takes brake levers with a fairly standard, for mountain bikes, 22.2 mm clamp size.
It seems really likely that you'll be able to find something that works without having to spend a big pile of time or money.