Umm, needs a new HD floppy, needs the battery fixed (previous owner ripped out out and destroyed the connectors), needs a new hard disk, needs a new mouse and keyboard... And that's all before I can use the poor thing.
Then, once it's up and running, it'll need the buster chip replaced (currently rev 7), and I want to network it, upgrade to kickstart 3.1, put in a gfx card, etc...
Hi, you know most of that stuff you can do quite happily with ebay and regular computer shops.
The battery is easy to get from a specialist electronics shop, and just needs to be soldered in. The connectors are actually a part of the battery, so you haven't lost anything there. The batery comes with connectors attached, which solder onto the board. This is quite an easy soldering job. Don't know if you've done any soldering before, but it only took me about 10 minutes to become fairly proficient.
I think you can use any regular ata hard disk for the 4000, can't you? Does it also have SCSI?
These days for a mouse and keyboard, you might be best served by getting (or making, if you're up to it), adapters for PC mouse and keyboard for Amigas. You can also find the Amiga items on ebay, and often also in general second hand stores, but too often for silly prices. You can save money if you can put in the time.
I think kickstarts are normally best bought from ebay. Then just read some instructions online, and plug them in. It's pretty cheap.
If you really need a more reliable deal, then shops may be worthwhile, but I've had good experiences with ebay and other second hand sources in Perth. Lots of people on this forum have also been happy with AmigaKit's service, and seems a very reliable source to deal with. The only 'current' Aussie Amiga dealer I have dealt with is the afore mentioned Amiga Innovations. Found him (Dwayne?) to be reasonable to deal with, but not competitive in terms of stock and price. For the classic stuff, I think he's probably just selling old stuff, and doesn't bother trying to get extra stock (this is just my impression though). Remember to shop around and get a good price (amd reliable deal). There are some real sharks in this small market.
Good luck.