Well, if it can't be done then what's the point of discussing it? But since our discussion is going a bit off-topic, how about this to contribute:
Enhancing Spell:
RDM 45) Subtle Sword- Self-only, potent Subtle Blow effect.
RDM 70) Boost-ACC- Does this exist yet? If not, it would help.
RDM exclusive, self-enhancing spells like Temper are the road to melee RDM...sorry, but it's the most realistic way to make it happen.
*How powerful are En-Spells right now? This should be the road to RDM melee, so a boost is in order if they don't make it worthwhile (worthwhile is just enough to not be wasting your time).
Job Trait:
RDM 30) Manablade- Attacks occasionally regenerate MP while wielding a sword.
This would activate around 10% and the amount gained would scale with levels (ex. Manablade II at 70).
I had no idea about this. It's interesting and disappointing at the same time!
Apparently you have dug around in the workings of the game a lot more than I have (not at all), so I'm gonna change my original (very computer sciencey, out-of-the-ass estimation) assumption that there's a 35% chance of them being able to do this to around 10% and closer to your estimate, lol. I had no idea that the game calculates an interrupt this way (now that I think about it, they do tend to happen closer to perceived cast-time...I just didn't know that's how it worked), and I definitely agree that this makes it seem like no, they are not keeping track of casting time continuously (the the start, stop work-around would probably not be able to be applied). Super interesting stuff though, thanks for explaining. I like the Internet sometimes.