I neither have FL nor Live, so mentioning them doesn't help me understand what you're after. Even if the bars already exist, I'd have to click and drag them to the needed value, right?
Did you try what I supposed? It's not that bad already, although each "bar" is a click and drag.
For a swipe I'm afraid you'll have to use the newest beta of SWS extensions which in turn requires a pre-release version of Reaper v5. It has a snapping freehand draw mode, which looks like this with square point shape:
It's the very first time I use this, so excuse my insecurity while going forward
That's without any click, just a swipe while holding a shortcut key (but needs the same square point setup procedure first). But yeah, it's bleeding edge as of now, not official. So you either will have to wait or dive into the beta test if you want to check it out.