I got my Zaurus SL-C1000 from PriceJapan.
It's the cheapest place, they are extremely reliable, prompt and fast but be aware that the waranty is only available in Japan so in case you encounter a hardware problem you have to send it to Japan.
If you want 1 year waranty in your country you have to buy from Dynamism(US), Streamline(US), Trisoft(Europe), Xtops.de maybe others.
If you are in Europe, I highly recommend Trisoft as you have 1 year waranty, a decent price, the right power adapter, english converted unit, many preinstalled applications, a contact on this forum, serious guys who love the Z and willing to help you out.
If the lack of waranty doesn't bother you, you can try to buy from Conics.net, or Lolzer.com who provide their own worldwide power adapter suitable for Europe.
My Z came with a power adapter that is only useable in Japan and maybe US but for sure not in Europe, I bought a worldwide power adapter from ebay for $35.
I have heard different things on these discussions about english conversions: Either PriceJapan does or does not convert. Could anyone who has purchased through PJ tell me if they do?
The Z was not converted to english but it's a piece of cake to do it by restoring a NAND backup downloadable from Trisoft website along with a well written User Manual in english. Basically, conversion is not an issue.
I plan on installing cacko or some such. Is it easy to do this on an unconverted machine or does the Z have to be converted to english first.
You will soon want to flash your Z, many languages are supported for each distribution(Cacko(available soon), PdaXrom, OzOpie, OzGPE). As you are interested in flashing with Cacko ROM, the conversion will be automatically done during the flashing process.
Is there a sleep mode that will allow me to save on batteries throughout the day and still have quick access to the machine? Does this depend on which OS I have running?
Each distribution has a sleeping mode
I have some experience with linux and currently have debian running on my laptop. Does someone else have a nice inexpensive conversion?
If so you will have no problem using your Z.
On some screen shots the fonts do not appear to be smooth. Is this a persistent problem?
There are extra fonts available in the cacko feed.
To sum up I think the best for you is to check
Meanie's website which contains every answers for those using SharpROM.