This is how I did mine...
http://dashmoto.net/baggage-handling
It's made out of 16x1mm tube.
If you don't need too much of it, just go to B&Q and buy a 2m length. It's overpriced (but still not that much money if you're only buying a little), but it's also just down the road and they're open every day
. That might be enough for you if you've already got the loops.
The tube for mine came from
http://www.metals4u.co.uk/ - I used five or six metres to do the whole rack, and I was ordering a load of other stuff for various projects.
You can bend 16x1 tube in a cheap pipe bender...
This is the proper way to do the frame mounts if you can find someone with a lathe:
Even if you can't you could probably make some with hand tools and a pillar drill if you were careful. You wouldn't be nicely counterboring the bolt heads like the first picture, but you could possibly do some like the second pic.
You can flatten the end of the tube in a vice and drill a hole through it. I've even seen people selling racks made like that. It is a ****ing awful bodge though.