Share 'Tandem bike rental for RAGBRAI'

Hello. My girlfriend and I are going to do RAGBRAI this year at the end of July. The idea of doing it on a tandem has come up several times as a way to complete it together in an enjoyable way. A preliminary search for tandem rentals brought up only results for those bike rental places on the lakeshore for tourists. Does anyone know of a bike shop in the chicagoland area that would rent a good qu…