I'm trying to add a lookup column in List A that would show Status column in List B. But the status column in List B is a "choice" and SharePoint 2010 does not allow choice as lookup. I'd prefer not to make it a text line where you type instead of a dropdown. I heard it's possible to used Calculated type instead but I dont know what formula to use. Does anybody know how to make it a lookup or perhaps an easy workaround?
It is indeed not possbile to lookup a choice field. You can indeed fix this with a calculated column.
Try creating a calculated column in list B, make sure it's output is text and add your choice field to the formula by dubbel clicking on the column from the drop down. In List A where you created a lookup column to List B, you can now select the calculated column as additional fields to include (open the existing lookup field).