In case you didn't know it, Spain have had many naval plans, most of them never materialized. From the Spanish wikipedia:
http://es.wikipedia.org/wiki/Anexo:Plan ... a%C3%B1ola
Centering only in the never built ones:
the 1914 naval plan expected:
-2 Dreadnoughts (None built i guess they would be more like superdreadnoughts)
-2 Cruisers (None built,Wikipedia does not specify if they were light or armoured)
-Some new class of submarine whose projected numbers is unknown
The Primo de Rivera-Cornejo Naval plan (1926) expected the construction of:
-3 Canarias class cruisers: Canarias, Baleares and Ferrol (this last one, Ferrol was never completed)
The 1943 naval plan -Here's where the main unbuilt projects are- It was designed by franco and his naval minister
-4 Littorio class battleships. 0 Built
-4 Carriers. 0 Built
-8 Cruisers (wikipedia does not specify neither the class or type). 0 Built
-84 Oquendo class destroyers (only 3 Built)
-36 MTB (only 9 Built)
-50 Type VIIC Submarines renamed into G-class. 0 Built.
-100 Torpedo Boats (only 12 completed)
-Auxiliary ships. Number, classes and configuration unknown.
Carrero Blanco Naval plan (1965)
-2 Carriers, 0 built. Similar to Colossus class carriers.
-2 Missile Destroyers, 0 built. Similar to Farragut class DDGs.
-8 Missile Destroyers, 0 built. Similar to Charles F Adams class.
-12 Baleares class Frigates. 5 Built.
-20 Frigates. 0 Built. Similar to Bronstein class Frigates.
-8 S-60 class submarines. Only 4 built.
-4 Amphibious assault ships. 0 Built.
Barbudo naval plan (1971)
-3 Destroyers 0 Built, class and similarities unknown.
-10 Corvettes, 0 built, class and similarities unknown.
-2 support ships. 0 built, class and similarities unknown.
Pita da Veiga naval plan (1973)
-1 DDG, 0 built. Similar to Kidd class DDG with increased AA.
-3 Frigates, 0 built. Similar to Oliver Hazard Perry.