A forum member pointed us to a Yahoo ad Library which entitles you to an on-demand banner advertising solution. You can choose ad templates and customize them for your company and service and then choose a publisher you want to run with.
The cost of the service is $167/day ($5k/month), according to the FAQ, though one wonders if this is a program endorsed by Yahoo. It looks like a reseller (adready.com) and has Yahoo branding all over it, but I don't see any Yahoo official statements regarding the service. It'd be nice for some clarification regarding this service as it appears that the reseller is selling Yahoo display ads under the Yahoo brand.
Does anyone know about this service or do they have anything to add?