The report of their being an apparent limit of around 24Gb in the size of image under DOS was a once off posting in the last two years or so, and there is no other information to substantiate this, or suggest any particular scenarios which may affect this. This may be down to few users continuing to use DOS for imaging with big drives.
Please bear in mind that DOS uses CHS addressing, and therefore the maximum size of hard disk it can technically access is around 132Gb. Service Pack 1 on XP actually introduced an updated disk handler which could handle bigger disks, and companies like Promise released firmware updates for their disk controllers to support 48 bit addressing as the DOS 32 bit limit caused problems with accessibility of bigger disks. Also, since DOS does not support SATA, which is now the de-facto standard for desktop and laptop hard disks, and SSDs, you are reliant on the BIOS having a compatibility setting which allows SATA hard disks to emulate the old IDE AT standard, but of course some limitation still exist. Clearly there are many variables which can affect the ability to use DOS to image larger disks, including the system bios and the hardware, so it is nigh on impossible to give you any guidance as to whether a workaround is possible or not. All modern drives use LBA addressing, and even that has started to run out of speed on really big drives, hence you will find that 2Tb and larger drives are now "advanced format" drives which write 4Kb sectors instead of 512b sectors. This is pretty much transparent to modern operating systems but some hardware may need updates to efficiently handle advanced format drives.
Ghost also has issues with UEFI bioses so UEFI should be turned off before imaging.
Overall therefore, moving to WinPE is the way forward - you are going to run into more and more problems with DOS and do you really need the hassle? Your version of Ghost does support the creation of WinPE boot media, or if you prefer to roll your own to get familiar with the process, you can follow this article:
https://www-secure.symantec.com/connect/articles/readyadventures-winpe
Since WinPE supports USB natively, it allows you to create a bootable USB drive and use that locally for storing or loading images which is often quicker and easier than using a network connection. WinPE does need drivers added for specific hardware, but this is not difficult, and you can always test candidate drivers by loading them from the command line. The following articles provide more information:
https://www-secure.symantec.com/connect/articles/do-i-have-correct-driver-winpe
http://www.symantec.com/business/support/index?page=content&id=TECH110134&profileURL=https%3A%2F%2Fsymaccount-profile.symantec.com%2FSSO%2Findex.jsp%3FssoID%3D1379325844236H648XIOBo89QYnlyyqy8JBXy4XpzTOpCi8Nmu