Is the manga Royal Seventeen over? theres 7 chapters...is that all?

look, 7 chapters where released, 2 from volume 3.
It's status in japan is 3 volumes (complete).... BUT it isn't completely scanlated.
Unless the info isn't really up to date. I can probably assume that the manga still isn't finished with just 7 chapters and volume 3 still has some untranslated chapters. You'll just have to wait for them to be released (if they ever do).

EDIT: And you know what? after a quick glance at the scanlators site, it is on their active project list and NOT the completed list... so I think it is now clear that it isn't completed...

it's completed.

http://shoujomagic.net/update/index.php?module=smmanga&func=display&sid=293

vol 01: ch01, ch02, sidestory01 (Club Papillion), sidestory02 (B-Men Kazoku)
vol 02: ch03, ch04, ch05, sidestory (Merumo-tan Comes Again)
vol 03: ch06, ch07, ch08, sidestory (Princess Paffy and the 40 Thieves)

it's true that it's still on the active project list, but according to the news post from ShoujoMagic here, the side story after v03 ch08 (which is Princess Paffy and the 40 Thieves) marks the end of the volume as well as the series.

The v03 side story has already been completed (though SM lists it as a separate project here), which means the Royal Seventeen series has been completely scanlated.

voila.