Hand held using an unconverted camera and IR filter:
I actually think long exposures not only result in sharp images, but the object motion is great to work with.
But motion does not have to be that noticable.
Sharpness is simply not a problem with using a stock camera and filter. Perhaps you don't like motion blur in objects, but that is a problem in regular landscape photography when maximizing DoF and minimizing ISO. Sure, if you want to maximize technical quality, a converted camera is best, but much can be done without a converted camera (see above).
And one of the appeals of IR photography is not its sharpness, but its aesthetic qualities of a lack of detail and and the tonal distribution (IR will never give the detail found in light photography).
These are really nice shots, and being in South Florida I certainly appreciate them. Motion blur with me is hit or miss, generally I try to avoid it unless i want to show movement. In the case of other people - certainly the shots you posted, I find it very artistic and interesting, maybe I don't have that confidence. I have shot on an unconverted camera, and certainly is easier if the filter starts in the 600nm range. I am just saying that a converted camera, does not have to be limited to IR. I think people tend to overlook this.