Attempting to print a custom paper size of 44" wide x 68" long results in no ink being laid down, and a hurried feed of all 68" of blank media, and a media cut. We're left with a 44" x 68" blank page.
Yeah, that happens sometimes. I've found that my blood pressure stays healthier with auto-cut turned off.
There is indeed a 2 Gb file size limitation in CUPS. I haven't seen a version of CUPS that handles bigger files, but it's been a while since I looked. In any event, installing a new version of CUPS requires a significant level of UNIX knowledge (but CUPS has a good web site, and there is a community of active CUPS users who contribute their expertise).
Image files greater than 32 kpels in the long dimension seem to be one of the things that can annoyingly cause an empty page to be printed, but I haven't done systematic testing to see if that's the only potential cause, or if there might also be a range of spool file sizes under 2Gb that cause this to happen.
Since I typically print big, I find it very common to have files that won't print in Lightroom. Since I like the easy output sharpening in Lightroom, I'll resize to a multiple of 180 ppi in Lightroom to keep the long dimension under 32kpels. Some people report being able to print files from Lightroom with a long dimension in excess of 32kpels, but I'm not one of them.
Printing in 8-bit colour depth is my next avenue of attack. This cuts the printer spool file size by almost half. If the spool file is still too big for CUPS, I'll resize more.
It makes me a bit sad to have big high resolution files that I can't print at the Epson 9900's best resolution, but that just seems to be the current reality.
Just to be clear, the only time that I save a resized file file is when I flatten and save my high-resolution Photoshop file down to a .psd file, since Lightroom can't read .psb files. Once Lightroom is able to read an image file I just resize the print output size in the Print module of Lightroom.
Hope that helps.