Easy just didn't happen. I tried the FireFox GSpace Add On, and the shell extension GMail Drive, but they ONLY treat their own files (although both are cool tools to use a gmail account as a file store). They do this by using a special email title, and by storing the files as attachments.
Also tried PhpGmailDrive 0.3.2, but this only displays files which are attachments.
Finally, I hacked PhpGmailDrive's usage of libgmailer (after upgrading libgmailer to version 0.9 Beta 2), which is a PHP wrapper for the gmail API. The documentation is not the best, and I was never able to get more than the first 50 messages, but by applying a "label" to the gmail messages of interest, 50 emails at a time, I was able to get the following hacked code to download the emails as files...
if ($gm[$a]->connect()) { //
$gm[$a]->fetchBox(GM_LABEL, "fix", 0); // name of constants can be found in libgmailer.php
$snapshot = $gm[$a]->getSnapshot(GM_LABEL);
$lastidx = count($snapshot->box)-1; //
//$gf->TreeData .= "// ".count($snapshot->box).".\n";
//$gf->TreeData .= "// ".$snapshot->box_total.".\n";
//for ($c=0;$c<=$snapshot->box_total;$c+1)
//{
//$gm[$a]->fetchBox(GM_STANDARD, "inbox", $c); // name of constants can be found in libgmailer.php
//$snapshot = $gm[$a]->getSnapshot(GM_STANDARD);
//$lastidx = count($snapshot->box)-1;
foreach ((array)$snapshot->box as $item) { //
$gm[$a]->fetchBox(GM_CONVERSATION, $item["id"], 0); // name of constants can be found in libgmailer.php
$snapshot1 = $gm[$a]->getSnapshot(GM_CONVERSATION);
foreach ((array)$snapshot1->conv as $item1) {
$fh = fopen("C:\\down\\".$item1["subj"], "w");
$body = $item1["body"];
$body = str_replace(""", "\"", $body);
$body = str_replace("
", "", $body);
$body = str_replace("
", "\r\n", $body);
$body = str_replace("
", "", $body);$body = str_replace("
", "\r\n", $body);
$body = str_replace("
fwrite($fh, $body);
fclose($fh);
continue;