Welcome to the forums. I'll take a stab at your question. The short, technical answer- there is no such thing as an ELSA that meets the "51% rule". These are actually two distinct and mostly exclusive ways of building and licensing a homebuilt.
An ELSA is a kit aircraft that meets the LSA rules (top speed, weight, etc.) and is an exact copy of a factory built design (SLSA.) In order to be licensed as an ELSA, it must be built as an exact copy of the factory ship. You can paint it a different color, but beyond that not much customization is allowed. The up side is that there is no "51%" rule and you can legally hire others to perform most of the construction work for you.
The "51% rule" applies to Experimental- Amateur Built aircraft. E-AB (the traditional way to license a homebuilt) requires that the majority of the construction be done by the builder for their own "education and recreation," ie. the 51% rule. The upside to this over E-LSA is that there are not the same restrictions of speed, weight, etc., and that you can customize the design to your heart's content.
Now, their are E-AB designs out there (both kits and plans-built) that meet the speed and weight requirements of ELSA aircraft and can be flown on a Sport Pilot license, but there are not ELSAs. And, to split hairs, there are some ELSA kits out there that could be shown to meet the major portion requirements to be registered as an E-AB, but that would be up to the individual builder to document and prove to the FAA. For example, the RV-12 from Van's was recently approved by the FAA to meet the major portion rule. So, you could build an RV-12, for example, with an O-200 instead of the standard Rotax, but at that point it is no longer an ELSA, because it does not conform to the original design.
Clear as mud?
It might help us help you a bit if you could clarify what you are looking for. Are you looking for E-AB designs that can be flown as a Sport Pilot? Or an ELSA that could be modified and licensed as an E-AB?
Sorry for the long answer to a short question.