Those rumors about Spain never had any legitimacy as far as I know. They seemed to be concocted by fans who merely wanted such rumors to come true. I don't think it would match anything in the park currently, nor would it seem to go along with where the park is headed. I don't think the park ever had such plans.
I guess you could say the brain for Spain stayed mainly all in vain...
Well in the previous 5 year plan the park had, the resort, full-year operation, two dark rides, and German train station were all supposed to happen along with the addition of a new hamlet, Spain being the most likely. However, that 5 year plan was shelfed due to the fact Verbolten did not get attendance above the 3 million mark.
The rumor first came about with Busch Entertainment partnering with Tussard in the late 80's and building Port Adventure in Spain. The design engineering was BEC taking the lead.