Problem running commands

[disdain]

I've been trying to build a minimal system using just a kernel and                                                                                           
busybox (for now), the ultimate goal being a boot disk intended for
hardware                                                                                 
testing.  However I've run into a fairly frustrating issue I can't seem                                                                                      
to resolve.  I'm trying to get the system to drop directly to a shell as                                                                                     
soon as the kernel is loaded, while still remaining within the                                                                                               
initramfs.  Everything works as expected until I try to enter commands                                                                                       
at the shell prompt.  All commands, but a select few (e.g. pwd, echo),                                                                                       
respond with "sh: <cmd>: command not found".  If I try "busybox <cmd>"                                                                                       
it works as expected.  All symlinks are in place and and $PATH is set                                                                                        
correctly.  Any ideas on why this might be happening?  Did I miss                                                                                            
something in the configuration?  Any help would be appreciated.