10x22x1 would probably do all you want to do. I don't know if you will be cutting threads but if you are, you might want to look at the range of threads. Also, a taper attachment will come in handy for turning barrels.
Invest in a quick change tool post too.They are really nice for quickly going from cutting/threading to boring or knurling.
Check out JET lathes. They are a little more expensive than Grizzly but are pretty good machines.