Well my idea for the split-tube, seat tube has come to fruition. Originally I had planned to use 1/2" tubes to make the split, but I didn't think they were going to be stiff enough so I went up to 5/8". I took it and tried to flex it with just one leg. It was a lot stiffer thean I thought. I believe the original plan would have worked . . . no doubt.
Here are some picture. This is the best I can do balancing the seat-tube, wheel, and camera in the wind, but you can see even with the "Over Sized" split tube I have plenty of clearance.
Right now for a race frame I really want to go with the 1/2" tubes, and I think I'm just going to finish this one up and make it another expeimental road/cross/ do-all-2-all bicycle.
It look like that back tire passes throught the seat tube, but make tires don't pass through seat-tubes . . . Is it an illusion?
Nope the rear tire passes through the seat tube!
Yeppers! . . . Got Clearance!