Sure! To generate test cases for the "Twin Prime" problem, we need to ensure that the generated datasets fall within the specified constraints and that they are varied enough to test the different edge cases of the problem. Specifically, we need to handle multiple input values and the termination condition indicated by the input `0`.

Here's a test case generator for the "Twin Prime" problem:

```python
import random

def is_prime(num):
    if num <= 1:
        return False
    if num <= 3:
        return True
    if num % 2 == 0 or num % 3 == 0:
        return False
    i = 5
    while i * i <= num:
        if num % i == 0 or num % (i + 2) == 0:
            return False
        i += 6
    return True

def generate_twin_primes_up_to(n):
    primes = []
    for num in range(2, n + 1):
        if is_prime(num):
            primes.append(num)
    
    twin_primes = []
    for i in range(len(primes) - 1):
        if primes[i + 1] == primes[i] + 2:
            twin_primes.append((primes[i], primes[i + 1]))
    
    return twin_primes

def get_largest_twin_prime(n):
    twin_primes = generate_twin_primes_up_to(n)
    if twin_primes:
        return twin_primes[-1]
    return None

def tcgen():
    # Generate a random number of datasets (between 1 and 10 for this example)
    num_datasets = random.randint(1, 10)
    
    datasets = []
    for _ in range(num_datasets):
        n = random.randint(5, 10000)
        datasets.append(n)
    
    # Append the termination condition (0)
    datasets.append(0)
    
    return datasets

# Example usage:
datasets = tcgen()
for n in datasets:
    if n == 0:
        print(n)
        break
    twin_prime = get_largest_twin_prime(n)
    if twin_prime:
        print(f"{twin_prime[0]} {twin_prime[1]}")
    else:
        print("No twin primes found")
```

### Explanation

1. **`is_prime(num)`**: A helper function to check if a number is prime.
2. **`generate_twin_primes_up_to(n)`**: This function generates all the twin primes up to `n`.
3. **`get_largest_twin_prime(n)`**: This function returns the largest twin prime pair up to `n`.
4. **`tcgen()`**: This function generates a random number of datasets. Each dataset is a random integer `n` between 5 and 10000. It then appends the termination condition `0`.

The example usage showcases how to generate datasets and print the largest twin prime pair for each dataset until the termination condition is met.