One of our vendors passes all their parameters as XML. I'd have to look at exactly how they do it, but if I remember correctly they build the XML in a report dataset and use a hidden parameter set to the value of that dataset. Then they pass that parameter to their SP.

Inside the SP they shred the XML back into the original Parameters. This way each SP gets only the parameters they need, and they have the parameter name, type and the Value.

The only draw back is having to deal with XML (personal Bias 😉 )