Thanks for the feedback Tomer.
We'll consider additional overloads in the future, but currently you can achieve the results you want using ContractBasedImportDefinition.
IEnumerable<Export> matching = container.GetExports(
object value = matching.Single().Value;
Admittedly this is very verbose, but if you want to you can package it up as an extension method on ExportProvider.
Hope this helps,