Armorcast makes some. Not prepainted. Actually they look like the same walls except these are cheaper. Look under walls at Armorcast.com.
Sir Randall is correct in general, but with the Warstore's current sale, they are about the same price, comparing 36" runs. Pegasus has a big advantage to me as painted (had my heart broken too many times...), but Armorcast individual pieces are shorter and therefore more flexible in use. *shrug*
But, as I'm generally playing on VSF_Gamer's table, Armorcast has the final HUGE advantage!
Doug