We're having no luck printing from LR4 to an Epson 9900 when print length exceeds about 30". Photoshop CS6 does not appear to manifest the same limitation. Attempts to print from LR4 result in a blank page, cut to the specified size (44"x68" in this case) but the page is blank with no ink deposited.
This is LR 4, OS 10.7.5, with the printer networked with all connections hardwired via ethernet. Drivers are up to date. Epson feels the limitation lies within LR's printing architecture.