Plug-in Hybrid from Riley Enterprises to Debut in June.

GLENDALE, Ariz., -- In less than 90 days, Robert Q. Riley Enterprises, LLC, a product design firm in Glendale, Ariz., will introduce its XR-3 plug-in hybrid, a sleek two-passenger, three-wheel sports car that is expected to generate up to 225 miles per gallon. Designed to be assembled by someone with average mechanical abilities and no prior experience, the all-wheel drive vehicle will be available as a kit or plans for complete do-it-yourself construction.