Here's a strange couple questions:
1. Where should the Covertec wheel be placed on a saber if it is going to be a staff?
Darth Maul's was at one end, near the emitter. That would be my suggestion; it means it hangs down lower, but the more length you have pointing down, the less it would want to twist itself around while you're moving.
2. Instead of a covertec wheel, or d-ring, what are some other ways to carry a saber?
BurceChuat's suggestions are what come to mind to me. You could do something like pouches on your back (similar to how you sometimes see swords carried across the back) but that seems more "cool" than "practical". Yoda carried his in his sash, although it seems like it might get tangled if used by anybody less cool than Yoda.
(And by "anybody less cool" in this case, I really mean anybody who isn't CGI!)
3. What kind of paint could I use on a saber that wouldn't rub off when the saber is used?
I can't help there--it's something I expect to find out myself for an upcoming project, if I ever get around to it.
4. Which sabers from US are immediately recognized, and shouldn't be in a non SW film?
Depends on your threshold for "immediately recognized". Consular, Guardian, Menace, Graflex, and Chosen One are all very close to movie sabers, and Omen is clearly the Thundercats' Sword of Omens. Getting a Crimson or Azure Menace as a single hilt might lessen the resemblance enough to make it not obviously Maul's saber. Both Archon variants are close to Luke's ROTJ saber, but not identical, particularly in lacking activation boxes; you could probably get away with them (especially the Archon v2.1) as being clearly lightsaber-ish but not exactly the same, particularly if you swapped pommels.
Beyond those are some, such as the Raven and Malice, that are very close to lesser-known sabers from Star Wars. (In this case, both are from games rather than the movies.) Then there are the crossguard designs, the Flamberge and Renegade; these will remind people of Kylo Ren, but they're not exact replicas of any canon saber thus far.
Of course, the true saber nerds will recognize anything you use unless you mill your own entirely-unique design, but I don't think anybody who say "wait, go back... That's
totally an Ultrasabers Scorpion!" is going to follow that with anything but "that's awesome, I'm going to go post that on SaberForum", so I don't think that's something to worry about.
5. Is the gold on the Sentinal LE, and the gold on the Shock LE the same color?
5. I've heard that the Shock LE's gold is significantly dimmer than the Sentinel LE's gold.
As a rule, the older the saber, the less vivid the gold. Aeon/Initiate LE v2s are the oldest gold-trim sabers still in production, and it's clearly golden, but pale. Aeon/Initiate LE v3 and Shock LE are kind of a deep gold. The LE v4s are a bright gold. I think that the v3s and the Shock LE are the same, but to be safe, I wouldn't count on any gold matching except for the sabers that are explicitly designed to match: the Aeon LE and Initiate LE within each generation, and the Sentinel LE to match the Apprentice LE.
