Just to update / close off this thread: I ended up grabbing an as-new-in-box Genz Benz Shuttle 9.0 second hand for a good price (for NZ). It's a *heck* of a lot more amp than I see us needing for a long time, but from what I can gather it's a bit of a NLA classic, like the Walkabout.
In terms of cabinets - again, somewhat limited by selection and don't want to spend too much more just yet. I'm torn between getting a better quality 210 or 212, then adding a second cab later, but also a bit wary of 450w @ 8Ohms. Other option is Ampeg PF410HLF cabinet (shame it doesn't have speakon, but oh well), unless you guys can suggest another alternative, preferably for less than $1300 NZD from this selection:
Amp Cabinets - Amplifiers - Bass | NZ Rockshop.
I'd have to research them more, but setting the filter on that page to $1500 and under, the cabs that jump out at me are the Mesa Powerhouse 210, the Ampeg PF 115 HE, the GK Neo 112, and maybe the Markbass 12 or 15. The Orange cabs could be interesting as well, but I don't know a lot about them (played their 15, I think, briefly -- sounded stout in the store, but not enough time with it to judge much).
The Mesa I've played -- good sounding, but quite heavy. Might be hard to find a second one later, too, since, as far as I know, the Powerhouse cabs are discontinued. The GK Neo 112, from what I've heard, should have a more balanced sound than the 15 (though the 15s will go louder). Markbass a bit middy -- tweeters aren't my fave -- but sound and work better in a mix than solo (very difficult to lose). Don't have experience with the Ampeg 15, but specs make it sound like it would have some depth.
The GK CX series cabs could be interesting -- only played through a few very briefly, once, in a store. Wasn't crazy about them, then, but didn't get much time with them. Worth looking into and are a lot more economical than the Neos.
Strange about the lack of Speakon -- at these power levels and with a class D amp, frankly, I'd have some retrofit to the cab. Worth doing for a good cab and safer for the users -- shouldn't be difficult or too pricey.
I didn't recommend a 410 because I'm not crazy about the form-factor, but if you don't mind the schlep -- and if you don't think something like a 2x12 or 2x15 rig will be loud enough for you down the road (2x12 I can maybe see in the loudest settings, but two good 15s -- the Ampeg looks efficient, too -- with 800 or so Watts behind them should be plenty for almost anything), a 410 gives you a lot of potential volume more economically than the other cabs. Two 410s, well...
The Warwick and other stuff could be worth a look, too -- just not familiar with it.
Others will have more advice/direct experience with stuff I don't.