Louis,
I'd agree that buying a totaled Lexus is probably the best route since you'll have all the parts you might need. But finding one can be tough, especially depending where you live. I'm in Albuquerque and have yet to find an LS/SC400 in any of the local yards, let alone a complete junked car.
From what I've seen, JDM motors are nice & clean and seem like a good option. Unfortunately, I had to worry about emissions, so I sourced a motor from a US-spec vehicle. I bought a complete motor on eBay from a low-mile 97 SC400 for about $1000. It came with everything – all accessories, uncut harness, etc. However, in retrospect I probably would've been better off finding a comparable engine with no/some accessories and buying them on my own. Even though this motor came with everything, it was pretty evident it had been sitting outside for some time. Everything was rusted/corroded. I've spent most of my time cleaning all the accessories & engine block. I did take the starter & alternator to Checker Auto and they both tested good, which was surprising based off how bad they looked from the outside.
As far as a parts list, I'm sure you got the basics, like a new water pump, timing belt, etc. Bigger stuff like a radiator, transmission, electric fan(s), etc are pretty much application specific. I've had to change my list around a little since deciding to put my 1UZ into a 91 FJ80 instead of a 98 4Runner.
Anyway, hope that helps. Good luck with your swap!!
