For pounding the banks with a floating line......

You can take a standard long belly line and cut off the first 5 feet of taper and use it for a streamer line. That is if you want to poor boy one together. Basically what you want in a streamer line is one that carries taper all the way to the fly. Most fly lines start to bleed energy pretty quickly in order to allow for a gentle presentation. If you are just pounding the banks and getting a few quick strips you don't want to have to strip the whole thing in again just to get off another cast. A long belly line with the end cut out of it allows you to pick it up and lay it back in the next spot while still turning over the fly. This was the general idea behind the clouser line when it came out. Simple but it works. The more energy you can carry to the end of the line the better.

Also Umpqua had a streamer taper leader at one time which had the same taper principal. It had a strong taper all the way to a short tippet section. They were generally only 7.5 feet long so that the fly line carried energy to a short leader section. An off the shelf leader will have about 5 feet of taper with maybe 4 feet of tippet section. An alternative if a streamer leader is not available is to buy a 10 foot flourcarbon leader and take out a few feet of the tippet section. Most salt water leaders will not have as much tippet taper and will generally work well for streamers. My gripe with salt water leaders is they are usually pretty stiff which makes them a little more difficult to cast accurately. If you boil them in hot water for 7-10 minutes before putting them on the line they will be soft for about a month. That just makes them easier for casting behind stumps, or hitting rock pockets. The difference of a few inches can often mean the difference in a take or not.