Kyle,
That is an interesting request. We have proposed and implemented DNN based solutions for several clients ranging from pure DNN implementations, custom module development and integration with custom applications. We are typically responding to requests rather than generating an RFP and most of our new development clients were business users that were unaware of DNN until we brought it forward as a solution. We did end up changing the format of our functional specifications document to be more DNN friendly and speak in terms of modules better.
If I was trying to create DNN favored RFP that lists out the business requirements I would try to do a little thinking on your end to segrate the functions into DNN's way of thinking. For example instead of bullet point listing out the functional features you want rather lay them out as a set of modules you want with functional bullets under each modules.
That said, unless you are personally designing the site and just looking for implementors why not keep your RFP very focused on your business needs and just let your vendors know you want the responses to be centered on DNN? I might would put in a few lines that indicates responses should break out the estimate by modules and identify which modules would be custom and which would use or existing 3rd party modules.
Good Luck,
Thayer Tate
VP, Project Services
SolTech, Inc.
thayer.tate@soltech.net
404-601-6000 x284