Yes, I found that, thank you. Turns out, I'm a knucklehead! Sometimes it just takes an embarrassing post to remind one of that fact.
I was testing in qemu, and forgot to change the default ram from 128mb. It booted fine when I increased the memory.
So, in case someone stumbles on this thread: Check to see that you have sufficient ram to load the initramfs if you receive the "initrd too large" syslinux error on boot.