Hi @GoIllini,

I have had a look at your PDF on the ideas site, which demonstrates what you are trying to do.
What you are trying to do is possible at the present time. There are no limits on the number of cascading lookups.
The trick is to have multiple lists that are looked up and not just one list.
The following link provides instructions on how this is done.
The images are broken at the moment since the last community migration but I will try to restore them.
 

EDIT:
I created a new tutorial here: 

@SimonMuntz thank you for the clearly defined tutorial to get around this software limitation. While I was able to successfully accomplish what I needed to do with a very small amount of entries in my data source, this method is very inefficient. In order to get around the multiple condition limitation on a lookup field, in my particular use case, I would have had to have a total of 6 separate lists!

My source list not only contained the various approvers that need to be selected by the users filling out the form, but also contained users that are needed for my workflow process only. It works great currently, with everyone in one list, and I just use a query list action to pull the roles in the WF. This makes it so that I’m not having to hard code approvers into the workflow or go to multiple places to replace people. 

But maintaining 6 separate lists will be a maintenance nightmare as there will be high turnover with these people. Cost of maintaining these lists outweighs the benefit of the users only seeing select users as options in their form. 

As you mentioned in your post, “I have been with Nintex for over 10 years, and this has been a request from day one.” This seems to be a very common request by customers for a decade. Love the forms and workflow products and is so powerful. This seems like functionality the development team can probably relatively speaking, implement. 

I’ll keep my idea out there in hopes of a lot more votes to get this implemented.

I appreciate your comments and tutorial. Very clear and concise. Will definitely use this in future projects that are smaller in scale.