Can anyone please give me some input about whether it is possible to add watch-only addresses into bitcoind?
1) create new wallet.dat
2) import private keys to it
3) set a very loooooong password. Something like "jfjflkjiu48t48476873284efbsdsdff8*DDD#*#*RF$*FH$NFN$F$*F$*F*@NF#*F*#FN#*fjdsjfkdsjl"
4) do not keep this password.
You will receive watch-only wallet.dat because nobody (even you) knows the password to spend funds.
PS. Do not use password from this example - it belongs to me and my wallet.dat
the complexity of the private key is all for safety ... especially for online wallet ...
where it can be done brute force attack starting from a dictionary basis key with a high probability of resolution.
for stronger security you should set a password with a GUID generator online ...
you will have a code like this 9bc0926f-4ab2-4aea-9109-e9fd50c44a23
difficult to attack