technically the glow plug RC engine is a 2 cycle diesel, and it is the lightest/hp IC engine available.Smaller but not lighter weight that I can see. That high compression comes with a weight cost, and thus a $ cost. Observe that we do not see diesel back pack leaf blowers, or diesel push lawn mowers.
cheap to manufacture, robust. with some minor "improvements" it would probably run a leave blower cleaner than a conventional 2 cycle. not specifically cleaner, but still a tiny diesel in a lightwieght package