Take a look at EPiServer Relate: http://world.episerver.com/Documentation/Other-products/EPiServer-Relate/ 

I've built forum functionality using page types a couple of times. 

Of course you have to work a bit but you don't have to live the bad practises especially concerning client side code of a forum package you buy or download.

Also you save money and dead weight compared to using Relate/EPi Community.
For sure you also get a more future proof solution that's easier to upgrade and maintain.

If it fits I would try looking for something that's hosted and that you just include using javascript (like how you'd use Disqus for comments).

Agree with Johan, also Relate is not Cloud-compatible so you will not be able to deploy to Azure if you use Relate+

Thanks guys!

From the call out in the Relate add-on area, I had the impression it was more social sharing based than a forum system, but I see there is a forum component there.  I guess my concern there would be whether we need everything that comes along with it or not.  Also, not being cloud scalable is not ideal, per Henrik's comment.

I was hoping to avoid building something from scratch, more for moderation functionality, etc, but we are considering it as an option.  

I think our first thought was to either integrate an existing forum platform (http://www.mvcforum.com/ is the leading candidate at the moment), or tie in a third-party solution, as you suggest, Johan.  Finding the specific product to try to integrate with is the bigger issue, so if anyone has a suggestion as that goes, I'm all ears.

Thanks again for the feedback!