I think you can get wheat that way as long as it is not soured at all. I spoke with a local farmer yesterday and he has offered as much wheat as I'd like, but he isn't sure if it is rancid or not. He is having it tested and is to let me know. Maybe ask where you are, too.
Yes. I had to clean it by discarding whatever floated and most of what was left germinated so I'd say i got about 75-80% usable. It converted just fine, just had a higher protein % than my brewing malt so it made a really hazy beer.
Ive also done this with wheat and rye with similar results.