Here are some pictures of the Chinese passenger foot pegs that were bought on Ebay. I don't really like buying Chinese stuff, but sometimes that's just what's a available. In this case, I thought they looked pretty good. They came well packaged and are nicely finished. I do wish the black was a bit duller, but you can't please everyone I guess. These may not be quite as strong as I'd like. I really think they will be fine, but I don't think I'd stand on them in any position but straight down over rough ground. On the other hand I'm 240 without gear.
The first picture I'm trying to show the male portion of the connectors. These are not true splined connectors. I think they're called pin and post. There are 4 places to put pins (the chrome pieces) on the male parts, but you only use 2 of them. By choosing which 2 you get a finer adjustment. That can be a strong joint, but it depends on the quality of the casting. The piece in the center of the picture is the part that lowers the peg and the piece on the right is what goes into the mount on the bike. It was drilled to accept the detent spring and I was able to install the plate for the detent ball to ride in, so they can be folded up. I didn't take a picture of that, but you can imagine that they will stick out a bit more.
In this picture, I'm trying to show the female portion.
These last two are just to show how they look installed. This is the position my wife chose for the installation and is pretty much a 45 degree angle. The length of the arm is about 1.75" center to center and this is probably an inch lower and 1.25 or so further forward than stock. Her initial impression was positive and it is close to the way she sat on my C10 Concours. We still need to do a test ride. With them mounted straight down, I think you'd get close to the whole 1.75" drop. The peg could be rotated and doesn't have to be flat necessarily. I hope this helps somebody and I'll report back in a few weeks when we've had a chance to ride with them.
Edited to add these pictures:
With the Box for reference
and folded