Yeah there are thousands of records involved, so its forced into record-picker mode.
I'll have to see whether they are okay with this setup or if they'd rather stick with record-picker-only, but I think I'm going to try your original suggestion with a little twist.
Here's what I'm thinking:
The [data entry] and [record-picker] fields will be placed side by side on the form within the same section by themselves to highlight the fact they go together. Then using form rules I'll make it so that when the [record-picker] is used and an item is selected it will populate the [data entry] field then immediately clear itself. So the result regardless of how the value was entered will always be a populated [data entry] field, an empty [record-picker] field, and populated lookup fields (assuming a valid entry was entered).
Conceptually it's sort of like how date fields have that little calendar button within them that you can click on to bring up a selection popup and then once something is selected it populates the field's entry portion. Ideally I'd have more control over the form and turn the [record-picker] field into a little box or something and place it flush against the [data entry] field to better mimic that, but I suppose this will have to do. Hopefully that made sense.
Then for validation I'd just have a rule that looks at a resulting lookup field and if there's no data in the lookup field then I can assume that an invalid value was entered and prevent the save from occurring.
A bit messier than I'd like, but we'll see what they go for. Thanks for the suggestion.
