Well, since I'm getting back into building bikes again, I took a look out in the shed at the frame of my prized creation, the chopper you see in my sig. A few years ago, my welds failed at the headset, so the bike has been just sitting. I'd like to fix it, and make it better, but to do so, I need to replace some tubing. Pardon my misused words, I'm a self taught builder. Don't know the actual names of what everything is called.
Nova cycle has the frame stuff. A cheaper source can be finding frames at the dump or on garbage night and just cutting the parts out. Not that the parts are expensive but the stuff at your neighbours driveway end is cheaper still.
Beware that both parts require expensive post welding recutting. Sometimes people don't bother on crapper rides but it may prove necesarry.