The behold runs a check on boot an removes suid shells in /bin (and probably other directories. We need to hijack a suid task that runs really early on to get persistant root (see first post).
The behold also uses some secure partitions and so you cant simply use fastboot or odin to flash a custom recovery. Its also not security ulocked
The only way to put a custom rom on it would be to get the hijacked persisitant root command to kill system processes, untar onto /system what you need and then retart the processes.
Everyone be warned.. a 'hard reset' or 'factory restore' ONLY wipes /data and cache. That means any changes you make to /system will remain after a factory reset, except any that get undone on boot (like the su). On the upside it means you could probably untar a modified system onto /system and most of it would remain. On the down side if you mess up your /system you're phone is essentially bricked untill we get at least one update from samsung.