Your back end product could be something like "managed customized cloud hosting" (a.k.a. 3 $5 digitocean droplets) $85/mo. I did something like this with a wordpress hosting product we launched. $50+/mo. We just used a specialized hardened image on digitalocean. The lowest product was a single $5 droplet for the wordpress install and a $10 droplet for the MySQL box.
Or hold back some of your recommendations, generate a report with contact information so they can get in touch with you and set up a service agreement giving them EXACT things to change. Try and set up a retainer for 5hrs/month @ $200/mo then tack on specialized hosting!