You know, sometimes I find myself in a battle of a lifetime only to realize I'm trying to defeat something all the while the entire point/task is being overlooked.
One removes a drain plug to, well, drain out oil. The AIM is to get old oil out. How did the oil get IN there? From the TOP I'd suppose.
Depending on the size of your dip stick tube you might find that you can reasonably use an oil extractor to do a top-side oil extraction. I do this on my cars (VW TDIs) and on my UTV (Polaris Brutus- diesel, not that that matters). I drain from below from my tractors because they are 4wd and the oil pan is split (could likely only extract oil out of one side, the side where the dip stick goes in to).
Another idea would be to try removing it after things have gotten sufficiently warm/hot. Yeah, not really the time you're wanting to deal with oil, but... Get it nice and warm and take a can of cold and hit the plug. Trying to get some thermal shocking going on.
That's all I have. Sorry if any of this has been presented earlier, but wasn't willing to verify by going back through all, nearly 1,900, posts!