Depends on your needs (I know you recently got the v6 downgrid so if that's your desire you may need a foam style cut-out case)- but I own a basic ryot case (
pic) and it stores anything up to ~10" very nicely. However I don't think it would fit your downgrid and in that case you would be better off with a pelican that you can cut to fit it. If you're looking for storage for your evo however, I have had very solid experiences with this case, it has a ton of padding and a hard padded exterior so it doesn't hit anything to suddenly and for that it would most likely work well. I'm not quite sure what the price I would grab it at would be, as it came along with a bubbler that I bought, I'd say maybe around 50$ is what I'd pay(checked and that is the price on them). It holds my dabber, nail, silicones, and other things nicely for on the go useage, and it just fits inside of a regular sized backpack. That aside I'd say their larger duffle bag styles are what I'd grab for the bong specifically, or a pelican and cut out based on your piece, although these are less stealthy options, that aside the cases on ssv's website seem good
Here's another link:
http://reviews.nuggetry.com/glass/ryot-bong-case-jackdaniel