I took my aluminum pot and drilled a bunch of holes into it to make a strainer. I have a keggle for the brewing. I have the 2x3' bag from Midwest. It works great!!!
I used my old 30 quart aluminum kettle to hold the bag in my keggle. Just drilled a lot of holes in the kettle with a 3/8" spade drill. Works great, leaves the space for the element and protect the bag. Plus its nice for draining the bag as well.