Hi Hilary,
I have the same requirement of showing one of the multi-line text column value from SharePoint list in InfoPath (calculated value control) via Data Connection.
When I choose to modify the existing Data connection, it lists all columns except this multi line text column in Data connection window. I do not get to see and hence cannot choose. I changed the column type to Single line text and it appears in the Data Connection window in InfoPath.
But, single line truncates the text box to 255 characters and some of the values in that column are more than 255 characters and hence I have to work with multiline text.
My org will not pay for 3rd party software and hence I cannnot buy qrules though I would want to :-)
Is there any other round about way of pulling this information from Sharepoint List to InfoPath?
Thanks