I've done two self guided bike rental tours, Europe in 2007 and New Zealand in 2011. Both trips were on high end bikes (R1200GS) but nothing else from the rental agency. The cost for the bikes was upwards of $125/day unlimited mileage. I put about 400-500km/day on the bike and both times the rental agency wasn't too happy about the amount of miles I put on their bikes. Other than a flat tire in Belguim that messed up my plans a bit (lost riding time in the Ardennes), both trips went well.
I'm tentatively planning a trip to southern Spain, Andalucia, for the early spring of 2014. I'll more than likely rent another R1200GS and it will probably cost about E100/day plus fuel, there will probably be an excess mileage charge as well. I'll work out my own route plan with probably two nights at each destination. That type of schedule works good for me, one transit day followed by a day of 'local' riding, exploring, getting lost, finding good local food, etc.
'11 KTM 690R