Is there any way to load IOS from rommon ("switch:" prompt) if the bin file is missing or currupt other than xmodem? Can you boot from another stack member, or set up a tftp load like you can with a router by setting environment IP and TFTP variables, then issuing the tftpdnld command. I did try this in the lab and it takes the variables, but not the tftpdnld command.
In a fixed configuration switch like the 3750 xmodem is the documented recovery mechanism for software image restore. Once a software image is loaded the switch will join the stack as a part of the IOS feature for the 3750 and sync its IOS with the stack master. In regards to the rommon variables.. you can "set" quite a bit of variables, but it doesnt do much if there is nothing in the rom image to use the variables. :)
For those in a DR mode, remember the com speed on your terminal application and on the switch (switch: set BAUD 115200) when doing this or else it takes a really really long time!
For more info check out this doc.