I've got a Stone Brew Flip top. Worked good the one time I used it. Too bad they use a glass/glazed on logo. So I don't want to put my beer in it. Why give them credit?
However, I would think a handy guy could figure out how to wire a rubber plug in- like a champagne cork? HBS's sell all sizes of carboy plugs. Stick a stainless bolt with a washer through the hole, a nut inside, some wire over the top, tighten bolt for a seal. Loosen the bolt to get the damn thing out. Instant 1/2 gallon 'Party Pig"!!!
So far, I've had more experience thinking than I've had brewing....you don't think they are mutually exclusive, do you?
72 batches so far,
48 wine, mostly Loquat, peach, plum, prickly pear
23 beers and ciders
1 Tequila, from a prickly pear wine experiment that didn't work. I call it "Prickly Heat"