I can think of ornamental grasses which grow more slowly than most, but none that grow more quickly.

I think if your goal is 5-10' in the first year, you'll have to start with mature plants. 10-15 gallon Miscanthus, and other plants which are able to reach those heights at maturity. I grow grasses in my nursery beds with the express intent of growing them to maturity, before transplanting them to display beds.

I understand you want to grow grass for height, but are you aware of/concerned with the width of each plant?
Many grasses grow quite wide.

Deb

I have plenty of lateral space for them to grow!

I have been poking around Miscanthus. We have a great growing season here, very warm, and probably starts mid april till mid october.

Any idea on how tall field divisions of Miscanthus will grow the first year? Assume no over watering, soggy soil, or other limiting factors. Thank you for the knowledge!

"Field division" is a term which does not give enough information to estimate the first season height of an ornamental grass. If it's the size of a 10-15 gallon plant, it will probably reach it's full potential size in 2 years. The act of dividing the plant will have an impact on first year growth rate, which would not be seen if you used a pot-established plant of the same size.