Chuck, a 311" extension would be 25' of fabric, which does not exist to my understanding. But, you can replace a 90 1/4" wide slide out with the Solera RV Slide-Out Awning #LCV000163288 for white like what you referenced. We do also have this same one in white # LCV000168106 if you'd prefer that.
Both of these slide outs have a 48" extension so it's a bit different than what you're looking for, but will still work great as a replacement. view full answer...