I didn't want to clog up your Mythos thread so I'm quoting you here where it's on topic!
If I were you I'd sell the PB1000 and get a PB2000 if your room is tight. It's almost the same footprint. You could get a 2nd one down the road for a dual setup if you find space and some money. Keep an eye on
their outlet I'm almost positive that'll scratch your itch for a while. If you can get $350-$400 (assuming it's in good condition) for your 1000 you're halfway there. Just sell it before you order a 2000. 'Nother $350-$400 and you own a PB2000.
I personally would never ever ever go without dual subs. I'm actually considering buying or building 2 more with similar, if not exact same performance. So take what I say there with a grain of salt. I love me some good clean bass.
I do believe you could benefit from an upgrade. It'll be similar to what you have now, but more everything so that should keep you happy for a while whilst you save up for a 2nd. You prolly see me type it all the time, but good subwoofage is almost always underrated. I really mean it. I don't think anything else I've done with my system has had as much impact as my subwoofage. I think there lies your opportunity. If the upgrade bug is biting, you could get away with a substantial upgrade for in the neighborhood of $400.
*Edit: They're similar enough that you could swap them out and I doubt your wife would notice! Oh, I'm bad, lol. Hey, I wouldn't suggest anything I wouldn't do! Of course YMMV and all that.