Heh this is quite funny! I have my marauder which I play as main dressed into cartel item chestpiece because it looks way more cool than the cybernetic end game pieces marauders get and I can still feel strange looks on me because of the chestpiece even though I have over 20k health with my fully augmented rakata/BH gear with campaign armorings
I sometimes have to ask people to inspect my gear when they begin to complain about my "gear"
The most funny thing I have seen around was on Tatooine when I saw a ~25 level trooper running around! Yeah a level 25 TROOPER with no advanced class
In regards to being a Trooper with no advanced class, a lot of people do that for fun. I think Trooper/BH are one of the easiest classes to do that with.
In regards to the other points, I have never had somebody complain about my gear. I like to give my characters distinctive looks (damn it, why is there no good light armour for my sorc?). My latest character (Marauder) is using the quest reward from the Revanite chain on DK. The only thing I got asked when I got picked up for a SM EC Kephess kill was, "Do you know the fight".
I just wish tanks would guard me when I am on this new 50 or on my PT. I'm forever saying "you may want to guard me" and then pulling aggro as they haven't. I even wait 5 secs before attacking, but that gets annoying on high hp trash.