In a few stolen minutes at lunchtime, I quickly tried dialing up the attached preset based on Lemmy's gear and tone. (It's likewise available over at the IKMultimedia Preset Xchange, if you're into that: http://www.ikmultimedia.com/Main.html?UserArea/user_area_presetXchange_AT3.php?pXcID=656)
Since Lemmy famously used "hot-rodded" mid'-70s Marshall Superbass 100w amps (on which the Marshall signature models were based), I picked the Vintage Metal Lead model as something vaguely similar and aimed the settings at something like the suggestions I found through some quick Internet searching: bass and treble off, mid-range all up, etc. It may well not matter how Lemmy's old amps were modded with such extreme settings!
Likewise, he famously used a combination of old Marshall 4x12 and 4x15 cabs, so I opted for two Closed Vintage models in this preset, cranking up the size of one of them with that new "Size" control thing.
Not sure how good a simulation of a 4x15 that is, but it didn't seem to hurt. Mics are just a relatively conservative combo of 57s up close and 414s backed off a bit.My bass is a mid-70s Rick with the bridge pup being a Bartolini humbucker of some kind (Lemmy used to use various bastardized things, like fitting in Gibson Thunderbird pickups; now he uses the stock Rick humbucking pickups), and playing through the preset seems to get a reasonably authentic Motörhead-ish sound. Your mileage, as always, may vary! (As often seems to be the case, messing around with cabs and mics may be as good a place to start as any.)
Admittedly, Lemmy's contemporary bass tone may well be useless to anyone but Lemmy.
It is a writhing hell of grindy mid-range that will make you think something has gone very, very badly wrong somewhere. Still, it's Lemmy; it's good fun. And it might be the starting point for a less, ahhh, distinctive tone. 
IMO, Lemmy's tone from the Hawkwind days is a bit more useable for most people, I think, but I haven't tried dialing up a preset for that. Cranking the bass knob back up on the pre-amp would probably be a good starting point! 
Actually, I did also try taking the basic settings of this preset and pairing it with an Orange Thunderverb 200 and an Ampeg 4x10, and that sounded pretty cool. You get the grindy mid-range thing from the Lemmified Marshall model and the deeper rumble of the Orange ... but that's me, not Lemmy, and havent posted that up yet.
There's a lot of fun for bass players to be had from the Thunderverb 200 model, though, IMO. 
