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?
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 0)
        throw std::runtime_error(
            "abortrescan\n"
            "\nStops current wallet rescan triggered by an RPC call, e.g. by an importprivkey call.\n"
            "\nExamples:\n"
            "\nImport a private key\n"
            + HelpExampleCli("importprivkey", "\"mykey\"") +
            "\nAbort the running wallet rescan\n"
            + HelpExampleCli("abortrescan", "") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("abortrescan", "")
        );
    if (!pwallet->IsScanning() || pwallet->IsAbortingRescan()) return false;
    pwallet->AbortRescan();
    return true;
}
static void ImportAddress(CWallet*, const CTxDestination& dest, const std::string& strLabel);
static void ImportScript(CWallet* const pwallet, const CScript& script, const std::string& strLabel, bool isRedeemScript) EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)