If you search bikeforums on "motor oil" there are a lot of threads discussing its use as a chain lube, and in those threads nobody reacts to it with the horror that some of you guys are right now.Personally, I can say that I went to a shop three weeks ago and asked for a lube- I got Pedro's Ice Wax at the salesperson's recommendation and it only took me a day or two to realize that it was the totally wrong kind of lube for the riding I do and the frequency with which I am willing to lube my chain (every friggin ride? give me a break!)
After reading up on it some more I just decided to wipe off the ass wax and try some synthetic motor oil I had in the trunk of my car- WOW, it worked! It did not get my rims dirty. Yeah, I got a chainring tattoo, but I don't give a crap about that. I would guess that you used way too much on your chain and didn't wipe off the excess. Yeah, it collects dirt, but only when I'm doing some seriously dirty riding and I would normally have to clean off the chain anyway.
The 3/1 mineral spirit/motor oil thing sounds interesting. I might try that out next time. One things for sure, the motor oil is a helluva lot better than the "specialized bicycle wax lube" the LBS sold me which lasts about 25 miles. So don't knock the homebrew!