I really don't know if this is the best place to ask this, but if not I'm sure someone will let me know... 

There are a few options - X-Mod, Dynamic Springs, form Master, Enterprise forms, a number of others.

I use Enterprise forms for all such tasks for these reasons: It has a robust customizable workflow engine which is extremely useful for many projects; it gives you the option of saving data in tables that EF creates based upon the form, rather than saving as XML fragments in a common table. Thus you can have a suite of forms and use database technology to join them for enterprise solutions. Finally, the many features of Enterprise forms are hard to match. you can review on longnhi.com.

That said, I used to use form Master and really like it; high marks for usability and regarding features it is worth a look-see.

I have been using XMod on my site (http://www.hikersresource.com) to manage reviews of hiking equipment. It would recommend the module but the storage of data as XML is kind of a limitation. There is an option available to export your data to a csv file, but I guess that doesn't help if you need another module to access it. Version 5 allows you to access custom data sources but it sounds like you would have to develop that yourself or maybe purchase an add-on for it. There is a also a version called XMod Pro. It sounds like the custom data source functionality may be included out of the box.  That may be worth a look: http://www.dnndev.com/Products/XModPro.aspx . One benefit to XMod is that it is supprted by an active user base and there is a lot of info you can get from others in the XMod forums. The support from the developer is also excellent. I had a problem with installation and my support request was handled very quickly, even though I submitted it on a Sunday morning.