Is there an efficient way to hide the encrypted plaintext length with a block cipher? In block cipher modes of operation for encryption on input of a plaintext of $N$ blocks (We assume that the input size is always a multiple of the blockcipher mode: $N·16$ bytes) the size of the ciphertext is $N+1$, where the extra block is the IV.

Is there an efficient way to have fixed (parametrizable) larger length output on variable length input, to hide the plaintext size?

For example, for a short plaintext of $16$ or $20$ bytes I want to generate a larger ciphertext like 128 bytes, so an attacker can't learn the plaintext size from the ciphertext size.

The only way I can think of is just to produce pseudo-random pad to increase the plaintext message to equal the size of the ciphertext you want to output.
Counter mode (CTR mode) seems like it will do what you want.  The length of the output is equal to the length of the input, plus the length of the IV.  If this is not what you want, you'll need to explain your question/requirements more clearly.

In practice, I recommend you use an authenticated-encryption mode, such as EAX or GCM etc.