Much thanks to Andy Tim, H. Peter Anvin, and Icecube.
Resolution: Update memdisk to latest version (tested successfully using the syslinux 3.83pre6 memdisk)
FreeDos (and possibly other images) may require memdisk with raw option to fully work with all options.
MSDOS/Win98bootdisk/Lenovo Maintenance disks all seem to work well with just memdisk.
I have noticed that all newer Lenovo laptops (x61, x200s, T60, T61, W500) that I have tried have failed to load floppy based images (anything that uses memdisk to load up the files). They will attempt to load the image and then lock up. Latest bios, latest ubcd, updated syslinux files, etc.
I have a feeling that a memdisk just needing a minor adjustment as there just seems to be a blanket failure on the lenovo machines and memdisk. Perhaps a memory addressing issue?
Regardless I would like to help to tackle this problem. How could we go about pinpointing this problem?