I think, there will be no tool with zero scripting. Even the most sophisticated tools require minimal scripting.. JMeter & OpenSTA are reasonable tools (Both Opensource). However both tools require scripting
Let's stop calling it "Scripting." This is a development activity. The construction of a performance test is a Micro-Scale development project with the same phases: Requirements, Development, QA, Deployment and maintenance. As long as we continue to call it "Scripting" we will minimize the expertise level required to do the job effectively. If you are not conversant with the language of your performance testing tool (and they all have a "language" in them) then you should not be using the tool because you will be ineffective.
Development skills, and particularly being proficient in the language of your testing tool, are in the foundation skill classes that need to be present before you ever pick up a performance testing tool, Open Source or otherwise. After all, you are being entrusted with the equivalent of a tactical nuclear device. You can use it to destroy yourself as well as the software under test, your production site, incur legal liability for a DDOS attack on a competitor and even have your entire organization blocked by Google and others. That type of potentially destructive force requires expertise, it requires guidance until expertise is established and it requires responsible use.
There is a tool that doesn't require any scripting called AppLoader. The scenarios for the test are created using screen capture images taken as you use the application. Furthermore the script can be parametrized using CSV or local variables. The tool isn't open source though but definitely worth a look. There are demos of this tool in the company's website NRG Global | Products Test Performance of Applications