Okay...perhaps I'm just missing the obvious here
For distance practice, I currently do work with the bag or a nice sturdy tree (veeeerrrry slowly and lightly) as part of conditioning as well as a way to develop a sense of distance for various techniques. I'm surprised at how much closer I need to be than I would think for some things like kicks.
Obviously, if you aren't in the right spot, your blows, kicks, blocks, what have you will not connect with the most effectiveness or power. In a real fight, that would be...bad. In sparring, etc. that can lead to injuries or simply embarrassement (both of which you will get over).
Also, partner work is another way to develop distancing, and that is helpful in that it lets you work with people who have differing heights, builds, reach, etc.
But what else can be done to work on this? Are there specific partner drills that any of you do to emphasize or work on distance, either directly or indirectly? Are there drills or bunkai in Uechi or other systems you train in that might help with this very important skill?