I once made a boot CD that created a RAM disk and then copied a lot of utilities into it. The idea was to have a user menu for the different utilities and having them on the RAM disk would make them load quicker than they would off the CD. This turned out to be a "solution" that created more problems than it solved. The main drawbacks were that creating the RAM disk and copying stuff into it off the CD took quite a long time, causing a tedious wait before you could do anything, and also that the RAM disk was created in extended memory and some programs (Ghost 8 in particular) like to have exclusive access to EMS, and refuse to run otherwise.
However, all the solutions I have come up with so far require the batch file to have access to a writable medium of some sort.
Other problems that I wonder about are: The version of DOS used to prepare the bootable disk - the MEM in some versions of DOS cannot detect RAM above 64 Mb and report all amounts equal to or greater than that as 64 MB. (My bootable pen drive uses DOS 7 that comes with Windows 98SE and reports 1 Gb of RAM correctly) and the slightly differing output formats of different MEM versions.