I've printed longer than 90.5 inches, uisng the Epson printer driver under Mac OS X.
My success with Lightroom on long prints has been mixed: there is a maximum number of pixels in the long direction with Lightroom, but I can't find out what it is. It's less than 30,000 pixels (strictly speaking, pels), but I only find out when a print job fails (the way it fails is that the printer spools out the nominal length of the print, but doesn't actually print anything. If you have cutting enabled, the printer will cut off the blank length as well).
From Photoshop I've been successfull with prints up to 30,000 pixels in the long dimension, and about 12 feet long. Some folks say that you can print more pixels in the long dimension from Photoshop, but I haven't yet tested with more than 30,000 pels long.