It's funny, I have a JL DVD (from a '94 concert) and at the time he was using a GK 800RB head. I think he had 2 cabs that were 1x15" each and I believe that he did use a Rat (Kim Gordon from Sonic Youth uses one also).
As far as Rob from Nomeansno, he uses a Marshall Valvestate head (no lie). By sheer coincidence, when I first started playing bass (switching from guitar) I had the same amp and when we played live, I had his tone nailed down.
So yeah Flipper, if you post a few details on the Tad bass rig, that would be super cool. I've looked around for a copy of the Tad documentary locally but haven't found any yet (I'd order one online but I keep forgetting about it)
Yeah, you can watch the TAD documentary at veoh.com for free. Just type in "Tad busted circuts and ringing ears". It doesn't tell you how to get the bass sound(s) Kurt Danielson had, though

. The only reason i know the details is because I'm a friend of his and i used to have a lot of curiosity about his sound haha.
Well, he had a few awesome different sounds. I'm not sure which one you're talking about, but I'm guessing it's either the one on "Inhaler" or "Infrared Riding Hood", so I'll just describe both of those. I'll describe them in order of albums.
His tone on "Inhaler" comes first.
First of all, for the bass, he used his infamous rust colored `62 Fender P-bass with a black pick-guard. It had active EMG pickups in it, if memory serves right. He used a pick as far as technique goes.
For the rig, it was somewhat complex (not anything near the Infrared Riding Hood sound though! You'll see what i mean..).
He used a Hi-Watt DR-103 all tube guitar head that was modified for bass. He ran an original 90's made in England Marshall Guv'nor pedal through the Hi-Watt head, that was his distorted signal. He also had a vintage Ampeg SVT-II running as his clean sound. Both of these heads were running into the
same Sunn 4x12 guitar cab. In order to run the two heads into that amp, he used a morley A/B/Y box. That's how he got the "Inhaler" sound.
Now for the "Infrared" sound...
He used three different basses for the recording of this album; The same `62 P-bass with active EMG pickups, and a black pick-guard (this one was tuned to E standard, but tuned to D on the E string), a black Fender P/J bass with a white pick-guard and active EMG pickups (this bass was tuned C-G-C-G, and intonated for that tuning), and a black Fender Jazz bass with a red pick-guard and active EMG pickups.
For his clean sound, he used two Mesa/Boogie 400+ all tube heads. Each of them were hooked up to separate Mesa/Boogie 8x10 & 1x15 speakers (one 8x10 and one 1x15 for each head). Again, that was his "clean" sound, but it was naturally overdriven just a bit. He used a Morley A/B/Y box to hook up the two Mesa's. For his distorted signal, he was simultaneously running an old 60's 50-watt Ampeg B-15 all tube head through a single 1x15 cabinet (the one that the B-15's came hooked up to), and the B-15 head had the same original 90's Marshall Guv'nor running through it, with the gain all the way up, and the mids turned all the way down. Now, all three amps were recorded at the same time. What he did to do this was he sent one chord to one Mesa/Boogie 400+, and on the other output of the A/B/Y box, he used a "Y" chord. One end of the Y chord went to the other Mesa, and the other end went through the Marshall Guv'nor, and into the B-15. After he recorded the track with all three of those amps, he would put another track over it. he went direct into the recording console/ mixing board with his Sansamp BDDI (the 90's version that you had to un-screw the back to get to the controls). He used it to get a "distorted tube-like" tone.
He told me that in this tone, you can't focus too much on one piece of gear, because the sound was made up of three different elements, and therefore each of the elements played an equal part in getting that sound. Get me?
Anyway, that's how he got those two tones. I tried to be as descriptive as i could, so let me know if it helped out any, and if you have questions, than feel free to ask. See ya man.