OK, I'll admit I'm borrowing an idea from JS8CALL here, but am tossing this out to see if that functionality might be applied to VarAC.
I agree completely that we do NOT want "mail for" beacons being sent on the calling freq, but perhaps VarAC could function as follows:
I want to see if another station is holding mail.
VaraAC could be commanded to send something like "M?" after my call (example WD4KAV/M?) for ONE beacon, at the next beacon interval. ( believe VARA-HF would allow this.)
If another station held mail for me, and copied my call with this added indicator, it would initiate a link to me, and once connected, send the mail. (A maximum size limit could be set, to only permit short mail to be sent this way.)
A more efficient (less channel activity) way to do this would be to have a station holding mai, to connect and simply send a special short mail message, containing the word YES, followed by a disconnect.
Just thinking out loud right now, trying to find the best way to check for, and receive mail, with the least impact on the QRG.