If you can find the frames that fit your tank, sure. I just bought those parts from home depot to make a few covers. The 8 feet long framing bars for $4 each. Corners are $2 for 4. A bucket of spline, should be good enough to make more than 5 frames, for $10. A rollerknife for $8.
The total cost to making 5+ frames, $50. The joy of actually trying something new and making them, priceless! :D