In order to use a wide aperture at 1/250 sec in bright sunlight (without using HSS), the best option is a neutral density filter. Keep in mind, though, that the ND filter will not only block ambient light--it will also block the same amount of flash output as well. I wanted to do this very technique with one caveat-- I wanted to underexpose the background by a stop. These requirements led me to purchasing monolights and battery packs. Now I'm able to create the lighting I want no matter what the ambient level is--it's quite liberating. The following was done with 3 monolights and an ND filter:





That said, you're wondering how you can do this with speedlights. My first suggestion: use off-axis lighting as your mainlight. Second suggestion: until you have an ND filter, stop the aperture way down, get closer to your subject, and forget the modifiers. Will it be the most flattering light? Nope. But you may get something like this:





To be fair, this was done with two speedlights, but both were bare In fact, the mainlight was probably only about2-3 feet from his face. The lighting isn't as nuanced as the first image, but it's still interesting (I think). It was a bright day, but the narrow aperture helps bring down the ambient to a level where you can still see some detail in the clouds. The reason the backround gets blurred (even at this narrow aperture) is because the distance from the lens to the subject was very short (it was a 50mm lens, and the shot is uncropped).