In the log I see things like:

    2017-09-13 03:54:33 init message: Rescanning...
    2017-09-13 03:54:33 Rescanning last 68616 blocks (from block 416339)...
    2017-09-13 03:54:40 AddToWallet xxxxx  update
    2017-09-13 03:55:33 Still rescanning. At block 418849. Progress=0.549138

I would be interested to see the wallet file name on each of these log lines.

Would there be any interest in merging such a PR?
"importaddress \"address\" ( \"label\" rescan p2sh )\n"
            "\nAdds an address or script (in hex) that can be watched as if it were in your wallet but cannot be used to spend. Requires a new wallet backup.\n"
            "\nArguments:\n"
            "1. \"address\"          (string, required) The Bitcoin address (or hex-encoded script)\n"
            "2. \"label\"            (string, optional, default=\"\") An optional label\n"
            "3. rescan               (boolean, optional, default=true) Rescan the wallet for transactions\n"
            "4. p2sh                 (boolean, optional, default=false) Add the P2SH version of the script as well\n"
            "\nNote: This call can take minutes to complete if rescan is true, during that time, other rpc calls\n"
            "may report that the imported address exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.\n"
            "If you have the full public key, you should call importpubkey instead of this.\n"
            "\nNote: If you import a non-standard raw script in hex form, outputs sending to it will be treated\n"
            "as change, and not show up in many RPCs.\n"
            "\nExamples:\n"
            "\nImport an address with rescan\n"
            + HelpExampleCli("importaddress", "\"myaddress\"") +
            "\nImport using a label without rescan\n"
            + HelpExampleCli("importaddress", "\"myaddress\" \"testing\" false") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("importaddress", "\"myaddress\", \"testing\", false")
        );
    std::string strLabel;
    if (!request.params[1].isNull())
        strLabel = request.params[1].get_str();
    
    bool fRescan = true;
    if (!request.params[2].isNull())
        fRescan = request.params[2].get_bool();
    if (fRescan && fPruneMode)
        throw JSONRPCError(RPC_WALLET_ERROR, "Rescan is disabled in pruned mode");
    WalletRescanReserver reserver(pwallet);