Greg-
Sorry I didn't get back to you sooner...my nephew stopped over and we've been talking photography all evening. (It's great to have someone in the family to share my passion with!)
The information you got in this thread is correct. The outline you see on the front of the front standard is from the compendium shade. I don't have one so I have no idea how they actually work...and my camera shows no signs of ever having had one mounted. I know there are pictures on the web that show the shade in place...perhaps on the review page on lfphoto. I think if you use Google to search for Calumet C1 images you'll find it pretty easily.
The small hole behind the back of front standard, at the top, has what appears to be a nail (although I'm sure it's a screw of some sort) in it on my camera; that's to hold the metal ring on the top of the bellows when you're getting bellows sag (generally after you've stretched the camera out and then try to focus with the standards closer together). I'll bet you can find a small nail that will friction-fit into the hole well enough to use. With my C1, I find that if I just fold up the camera for a few hours the bellows don't sag when I open it up again...it's definately a problem after doing macro work, though.
One question for you: Did moving the tripod block backwards help you with the stability of the extension rail? Hopefully the instability you were seeing was just from the camera being unbalanced and isn't a problem with the block in a more central position.
Enjoy your camera...I know my Green Monster is my favorite piece of equipment. (This coming from someone with 3 8x10's, 3 4x5's, and more MF and 35mm equipment than he can keep track of...I'd rather use the C1 than anything else I own.)