Peter Reinhart has a number of recipes for spent grain breads in his whole grains book. About 10 years ago I called one of the local brewpubs and got a 5 gallon bucket of spent grain from them. (They usually just give it to local farmers to feed pigs, though they do use some of it in the bread they bring to the table and in some of the sandwiches they serve.)
I tried several spent grain bread recipes, but I think the most successful recipe I made was a variant on bran muffins. I think all the barley made for a sweet muffin. See Spent Grain Muffins
I did discover that since spent grain has a lot of hulls, sometimes it gets a bit chewy with stuff stuck between your teeth, almost like eating a bread with caraway in it. I took some of the spent grain, dried it in the oven and then ran it through the food processor to chop it up a bit, that made for a softer less toothsome bread, but it would take a lot of time to do that with a large quantity of spent grain and I don't know how long it would last after being dried. You can also run it through the food processor while its still damp, but it gets kind of messy to clean up.
From discussions I've had with others who bake with spent grains, depending on what kind of grains they're using in their beers, there's quite a bit of variability in the taste and texture of the breads made with spent grains.
Interestingly enough, there was no 'beery' flavor to any of the breads I made.
Beer makers also use a lot of different types of yeast in their beers, the local home-brew supply store must have two dozen yeast varieties, and that's just a small selection of what's available online. I don't know what impact different varieties of yeast would have on making bread, that could be a subject for a lot of experimentation.
I can't help you on using bread to make beer.
