Frank: either you've fixed it, or its magically started working again, so thanks anyway - I've managed to purchase the Acoustic Kit now.
Having played with it for a whole hour - I will give a brief review for the benefit of anyone else who might be interested in snapping up one while the special offer is still on.
After an initial hiccup (see above), the purchase was straightforward. I've yet to discover exactly what $39 translates to in local money, but the email with the download URL came almost instantaneously and the download was quick.
I went for the SL Acoustic Sample Kit
in sfz format which decompresses into a 75Mb sample library, and comes with 8 sfz files. This is basically one big sfz file for the whole kit, plus 7 with individual kit pieces separated out. This will be useful for those who want to separately effect and set levels for each drum by loading them into multiple instances of Dimension. As it happens Dimension won't use extra RAM even if you load the whole kit into each instance, as it detects that it already has the same samples loaded. The WAV files are all sensibly named which will be helpful for those wanting to customise the sfz file further.
The samples are already compressed and EQed ready to rock. I can see this as both an advantage and a disadvantage. On the positive side, its been done really well, so no more spending hours trying to get the kick to sound right. On the negative side, those who want to fine tune the sound to their personal taste will have less scope (maybe that's another project for Frank - a completely unprocessed sample kit). One thing I wasn't quite so sure about was the fact that the samples are all stereo and the toms in particular are panned quite drastically. You can fix this up with some sfz opcodes though so its not too bad. If I was sampling a kit I think I would take mono samples and pan them, leaving a reverb effect to create the stereo impression, and saving 50% RAM, but that's just my opinion.
The drums are more or less mapped out to a standard MIDI setup. There is only one kick drum, so it occupies B2 and C3. You get a choice of two snares - one on D3 and one on E3. I'm still trying to work out exactly what is going on, but it seems that the rim shot sounds are kind of mixed in with the normal sounds, and you get to hear them is you hit with the right velocity. Its perhaps a little unusual, but works well if you are playing the sounds in on a MIDI keyboard.
You get 5 toms which is extremely generous. The three lowest toms have a really nice undamped ring to them which works great for songs that require a powerful battering of toms.
The china and splash keys actually have about 3 different sounds each available at different velocities. This might mean you need to fix up the midi of anything you play live as you could easily not get the sound you wanted. Similarly, the ride has samples hitting in different places and with different parts of the stick. This gives a great natural variation to the sound if you vary the velocity as you play. There are some cymbal swells programmed to the lowest note velocities. I haven't got round to hearing them yet as my MIDI keyboard doesn't easily emit notes of the right velocity. You also get two crashes - 16" and 17".
The hi-hats are fantastic. You not only get the standard closed, open and pedal, but there is a separate closed edge hits and even some samples of the bell of the hi-hat being hit. The samples also include some half-open hits. This gives great flexibility to get exactly the sound you want.
I'm amazed how much has been fitted into the sample set. There's even a tambourine and a cowbell. There are cymbal chokes which are recordings of that cymbal being choked rather than just a key that chokes the sound of one being played. You even get some tom flam samples, which I was a bit surprised by as I think programmed flams sound just fine to me, but they add to the overall versatility.
All in all, I would have to say this seems great value for money. I might add a bit more here once I've had a chance to use them in a song. The only downside for me was the discovery that its impossible to play them with my V-Drums unless I have my latency set really low (i.e. 2ms max), which means I will need to upgrade to a more powerful PC.