As Larry suggested, go for the Faun, if you want modern stuff. It's quite reasonably priced, especially for what you get, and trust me, you get a lot. I got mine when it came out. I haven't built it, as I don't quite have 4 months to dedicate to it. There's more than 800 peices in the kit, and it really looks superb. I saw a few of them built up, and they are really massive.
If you pick it up, let us know, I have a couple of good resources for the Faun online.
If you're looking for older tank transporters, there's the famo and trailer from tamiya, the dragon wagon from tamiya. By the way, also a bit more modern is the chinese tank transporter also by Trumpeter. It's an ok kit. I built that one as well. Quite a beast as well, and definitely something different.
If you're specifically looking for the HET, I'm afraid that Acurate Armour is the only way to go. I wish someone would release this kit in plastic, as AA is ridiculously expensive.
You can't link from the AA site, so I couldn't post the pic of the UK rig, but it looks the same to me