High temperature heating elements

SiC elements can go a bit higher than that but not by much IIRC, I have seen them come up on ebay occasionally. MoSi2 elements can go higher depending on the element details upto maybe 1900C. I did correspond with a guy in Hawaii that used MoSi2 in a glass furnace and did the research with Kanthal as they have good information readily available, he then bought the equivalent from a Chinese supplier to save money. The control gets more complicated from SiC to MoSI2, IIRC SiC can be controlled with a simple phase angle controller off the mains, I asked Kanthal and they cut them to your requirement regarding voltage. MoSi2 have a low resistance when cold which increases as it heats so a typical controller involved a thyristor controller on the input to a suitable step down transformer which would give a suitable voltage for the hot element.