Here is a link for a good site that has almost everything.
Not exactly the same but these are draw latches.
The grates are just angle iron welded in a frame with expanded metal welded inside. The bottom rack has a couple pieces of angle crossing in the middle for added support.
The burner is partially made. I had purchased the venturi from Tejas Smokers and put a piece of pipe on it for the burner. I drilled two rows of 1/8" holes every 1/4" down the length of the pipe. But it is easy enough to make without the venturi. Do a search for the Frankensmoker that was built by SQWIB and you will see how he builds burners. I will be trying it his way on my next build.