Sap Dashboards (Xcelsius) certainly has its limitations. I will be the last one to argue otherwise. However, i often run into misconceptions about what those are exactly. A good example if the 500 rows limit. By default, Xcelsius is preconfigured out-of-the-box to limit cell bindings to 500 rows in the excel model. However, you can change this initial setting to your heart content. Why was this low limit set to begin with? Well, there are many reasons why you would see degraded performance in flash in general, and Xcelsius in particular, as you cram more functionality and data into your .swf file. The larger and more complex your .swf is, the more work your client computer has to do in order to manipulate and render the functionality desired, and to keep things simple, a 500 rows limit on most component seemed reasonable initially. As more sophisticated business intelligence applications are being built using Xcelsius, this limitation seems out of touch.
Does this mean you can have limitless dashboards with tens of thousands of rows of data in them? No, it does not, this is just an illustration to make a point. Realistically, your grid components should not exceed the low thousands if you are expecting good performance, and of course, many parameters will go into the sizing considerations such as the number and kind of components you are using, the complexity of functionality, as expressed in your model, etc. You can find the sample files here.