Cask Ale? Creative and reasonable thought. Hadn't even occurred to me, but I love the idea. At some point, I have GOT to try that. If I rack cold from a Keg into it, it should be pleasant enough. The point of cask ale is that it isn't "normally" carbonated, right?
I can't thank you all enough for your insight - I'm really leaning towards the fermentation vessel route. I only have one fermenter at present - a 6.5 gal carboy - and that extra headspace in this thing would be welcome. I will probably drill out the plastic breather in the top to accommodate an airlock.
joe_feist, if he didn't deserve lifetime access to my beer for this, he would certainly get it for loaning me his high-end Stihl chainsaw and helping me through my 6 cord of wood for next winter. Thanks for the positive ID on this rig from your military days, and thank you for serving.
Keep the great ideas coming. I will post with results from any use to which I put it. Leaning towards another IPA batch (got another body who's good for a growler of that every week) soon.
If I ferment in it, can I open the spout, clear out a bunch of the yeast, and consider that racking to secondary? I know that they do something similar in the conicals.