If you can have a cat, get both. If your landlord doesn't visit often, just say you're cat-sitting. If you get caught a second time, say it's temporary while your friend is out of town on business. If it happens a 3rd time, say the owner won't take it back and you're trying to find it a forever home...
Keep your place super clean, make sure there's no litter smell. Eventually, landlord will realize 2 is not so bad.