I know exactly how you feel about the belt clip. In fact, that is the only part of my costume that wouldn't meet the requirements for a Formal Application to the RL. I also love the D-ring. It's classic, you can't beat it for the nostalgic feel. But really, it's not practical in my opinion. And as far as that being a "New Republic" standard, I personally think it's ridiculous. We're basing an entire standard on ONE Jedi.
Just because Luke couldn't seem to find a covertec, or he seemed to prefer the D-ring, doesn't mean (in my mind) that it should be THE choice for all New Rep Jedi. For all intents and purposes, the only thing that makes my costume not "Old Rep" is that it's green and black. (Which, in following with Corran Horn's personal background would make it perfectly normal for an Old Rep Jedi, since his grandfather's robes were of the same nature.)
Some of the costuming standards need to be updated and broadened slightly to allow for a tiny bit more wiggle room. The New Republic storylines are just FULL of Jedi wearing different colors and different styles.
(Ya, I know, we need to set the standard somewhere, but it's like saying that just because an airplane doesn't say American Airlines on it, it can't be an airplane.)