I'm not even sure how they were able to create a single file that large under PCDOS unless there is some clever code within Ghost which gets around such limitations.
I can't recall the start date, but this was something that came out of an internal effort called "Project Phantom" where two of the technical leads on the cloning engine worked on a ground-up redevelopment in parallel with the main line of work on Ghost 2002, and 7.5 (and on a little bit). The main idea was that it would be a completely standalone NTFS implementation aimed at disk cloning (plus the important ability to do nondestructive restores, useful for OEM recoveries and one of the major features of ImageX).
One of the first capabilities of that was just the ability to do native basic NTFS read/write, and after the release of Ghost Enterprise a subset of that project was carved off and retrofitted into the classic Ghost line for the Ghost 2003 consumer product (aka Ghost 7.6, internally) and that continued to be expanded into Ghost Enterprise 8.0, along with having a lot of those capabilities spun out into the general tool OmniFS bundled in the Ghost Enterprise version to do arbitrary modications of NTFS partitions - read/write/copy/move NTFS files from DOS.
So, when Ghost 2003 and any later version wrote an image, you could point it at an NTFS partition and it would be able to write an image of any size to that (although in those earlier versions, it sometimes required some encouragement with -split=0 since it did still prefer to split at 2Gb so that things could be later copied to FAT partitions).
Now, both Ghost Enterprise and Ghost 2003 were cancelled in early 2004 (and Ghost Enterprise renamed Ghost Solution Suite to "free up" the Ghost brand for the PowerQuest product to adopt it; Ghost Solution Suite 1.0 was, despite the 1.0 version number, considered end-of-life when it debuted and our revenue really slid thanks to it being end-of-life and thus the sales people got not commission for selling it, plus of course the VP responsible was telling larger corporate accounts not to buy it and go for iCommand instead - that product being later withdrawn since it was unfit for sale).
However, the dev manager for Ghost at the time kept Phantom running as a "Skunkworks" deal, and just before our staff Christmas function at the end of 2004 (when the VP in question was visiting) it got a revealed in a demo to him, described in this edit to Wikipedia (which was later deleted, but I can testify that it's 100% accurate). The VP's reaction could basically be described as "throwing a tantrum", since we had "disrespected his authority" by working on any cloning-related code, and that everyone had to stop or he'd simply close the site and fire everyone. Note that at this point, he was responsible for 4 products; Ghost, PCAnywhere, iCommand, and the ex-PowerQuest stuff, of which iCommand and the ex-PQ projects were losing money hand over fist, PCAnywhere made a little (not big money, but OK) and Ghost made about 6x what PCA did, so Ghost was the sole reason his group was revenue-positive.
Basically, after this one of the two lead developers on Phantom code resigned that afternoon, and the guy who put in nearly as much (the guy who originally wrote Ghost Walker, and did almost all the early work on NTFS support in Ghost) went about a month later since they read the writing on the wall. Fortunately although that was a big hit to us, the work done to make Ghost use that product in 7.6/8.0 meant that once Ghost was uncancelled after the Veritas acquisition were were able to salvage and use most of the work.
[ Fortunately iCommand didn't last long, since despite big customers having been told Ghost was cancelled and that iCommand was the replacement, it was a gaping chest wound of total fail that was totally unfit to be sold. The security vulnerabilities in it were utterly staggering - we found 10 major ones (from hardcoded backdoor passwords to stupid things like writing user credentials in plaintext to logfiles on the very first day anyone in our team looked at it, and even a year later you could take control of any machine it had under management if you could sniff a URL since it did everything over plain HTTP without even digest auth; credentials were still being encoded in URLs in the clear. Fortunately the Veritas guys saved us from that too. ]