I'm new here. But spent many hours searching through the available modules in ExtensionForge and here in the store. Generally I'm wanting to do the same as you want to do. Accessing an external MS SQL Database and being able to search/view/add/edit/delete records in a master/detail style while taking into account the rolebased permissions of DNN users/roles.
What I have found (and bought) so far is:
"XMod Pro 4.0 - Forms and Views for Databases" (USD 149.95)
"OnyakTech Complete All Modules and Skins, Server License" (USD 149.95)
The latter is a package of lots of modules that can be installed seperately as needed. I bought it because this package contains these modules that match the topic: "DataViewer 4.5.4", "PDF Reports 3.5.5"
Maybe all of this is a bit of overkill, but just try the trials of the modules I mentioned and I'm pretty sure you'll find something that matches for you. From the opensource/for-free faction, I only found "DotNetNuke Form and List 6.0.3" that matches the criteria halfway, but as far as I understood, it only supports tables that are integrated into the DNN database (not an external MS SQL database with master/detail stuff).
I hope this will help you to save some time and to guide you into the (hopefully) right direction. Good luck.