Your comments

Would it (in theory) be possible to code this without bound parameters?

Basically fetching all available options of this entity and then display them in some html control?

Any update on this? 
Did MS allow this yet?

Great Idea. I actually just submitted the same (didn't see this before).

For us the Use Case is: Sales People can easily reorder lines in the Quote.

Use Case: Sales People can upload the signed Quote document easily in the SharePoint and the file location (URL of the SharePoint is stored).

Another one: Same for NDAs that are uploaded to the "Account" entity. We could easily filter, where we are missing an NDA.