Fatter lever bodies on non-integrated levers seems going against the grain to me.

The fatter bodies on STI levers jibes with their complex internals as well as rider's wanting to have continuous, comfortable access to instant shifting.

Whereas, traditional road bikes, i.e. racing bikes, can have smaller lever hoods, mounted lower down along steeply-descending "ramps", to facilitate the rider leaning forward aggressively while sprinting (or ascending steep climbs) while off of the saddle.

Then, when the rider needs to recover from the intense efforts, the longer-reaching diagonal return of the rider's hands back up to the bar's tops allows a maximum of abdominal relaxation in preparation for the next effort.

The modern "touring" trend of horizontal bar ramps with huge lever bodies does facilitate continuous use of the lever hoods as a hand rest with continuous access to shifters/brakes, but does not facilitate the needs of an aggressive racer, who needs a lowerer hood location for sprinting and a larger rise back up to bar tops for recovery.

So, with plain aero levers, the thin ones are ideal for racers, but will leave the casual and touring riders wanting for a taller, fatter hand rest with brake lever access.
For the tourists and casual riders, the Cane-Creek and Tektro copies (that mimic a Campag Ergolever shape) would appear to be near-ideal, and might not cost any more than a pair of just the proper hoods for some vintage lever.