Don't know how long it has been available, but I found out recently (by accident I add!!) that it IS possible to do a remote scan!
If you open up a telnet session (only done this via winbox from another Mikrotik) using the IP address of the remote unit (does not seem to work with the mac address) and then go to Interface : Wireless and then Print (to "see" the wireless interface(s)) and then type Scan 0 (or Scan 1 etc). The terminal session goes quite for a little while (ie you might think it is not doing anything!) and then all of a sudden it reports back what it has found. It seems to do multiple scans and then report back all of the results.
Be nice if it could be done when connected to the remote unit directly via winbox rather than via a terminal session, but it is still a great relief to have the facilitiy available!
Loop Scorpio Ltd
providers of rural broadband