I hate to say, it depends on the room, the wall, and the monitors.
It can work... MoPads or something may help also if you need to "detach" the monitors more.
THIS PHOTO shows my Wharfedales supported by TV wall-mounts from IKEA. I think they were around $25, which is next to "free" for wall mounts.
Only problem is the angle isn't adjustable. You have to have someone hold one up and eyeball it until the height is correct.
Also consider that depending on the situation, wall-mounting doesn't neccessarily save space - In my situation, I'm 6 feet back from that wall. Depending on your situation, your mounts and where your studs are, obvioulsy you can cut that distance down considerably. But just try having someone hold a speaker where you think it will work, and see if there's a mount available that will get it there.
Make sure you carefully consider the what's and where's before you start drilling.