Well, yeah.
I've been practicing everyday since May. In April, my max no-spin distance (as defined by being able to get 9 out of 10) was about 2 to 3 meters (6 to 9 feet). Now its (only) 4 meters (12 feet). If I go to 18 feet, I can only stick half of my throws.
If you think about it, in terms of self-defense, this is plenty of range for any indoor confrontation, and for most outdoor confrontations. Ralph talks about it more in his book: If you throw a knife at someone whos 20 feet away, that is (usually) an offensive move, not defensive, because you could probably run away. Furthermore, attackers usually wait until the last possible minute to reveal their intentions (I'm not going to say 'give me your money' from 20 feet away). If you think about it, the chances of you throwing a knife from almost point-blank is pretty high.
On the other hand, me and you both would like to extend that range! Why not?
That being said, you can look at some vids to compare short to long distance no-spin throwing:
http://www.youtube.com/profile?user=zabaksmers
Vid #1 is our beloved Ralph Thorn. Vids #2 &3 are Yuri Fedin. His long range throws are done with a blade-grip and 1/2 spin, however.
Also
http://www.youtube.com/user/mumyouan
This is Houzan Suzuki (who has his own youtube site and website, I guess mumyouan is his translator or something). He mostly throws shurikens, but his "shurikens" are so big and heavy that they are knives to me. (His vids tell you range and weight of his blades, which is nice) Anyway, compare his body mechanics in his 6 meter throws to his 18 meter throws. He is apparently a fan of Ralph Thorn because he has a link to Ralph's site, and his long-range technique is straight out of Ralph's video, in my eyes. (Whereas his short-range technique is the traditional Japanese technique).
To sum up the long range throw, in my words (which come from seing these vids, not experience - maybe Ralph can add to this), the movements of the legs, hips, and shoulders are exaggrated, while the motion of the elbow and wrist are not exaggerated. The throw looks like it starts lower (i.e. the hand holding the blade is held at chest-level rather than ear level), and the release is sooner (It looks to me like the throw takes place entirely behind the head - i.e. by the time the hand is passing the ear, the knife has already been released). Also, the follow through and leg-work is more dramatic (Both Ralph and Houzan Suzuki finish their throw with their bodies leaning left, their right legs in the air, and thier right hands down at their left knees). And the knife itself is released when it is pointing vertically (or even before).
Another thing I notice is that they keep the plane of the throw truly vertical for long-distance; whereas for shorter-distance, the plane of the throw is at a more natural offset. I think this is why they lean to the left, and I think the right leg is raised to couter-balance the body.
Anyway, I personally don't stress about the long-range throw. I just try to add a foot to my range every week or two. Ralph, how did you get your long-range? By working backwards or just by doing it (in other words, do you think the ability to throw close-range is a prerequisite for long-range?)?
Hope this helps, and I would like to hear any tips because I'm pretty much in the same boat.