Spudz

yes, it can be done . There is a ton of information about the 280ZXT swap into a early Z. Depending on price and condition of the donor drivetrain it can be done for a couple of grand if you can do all your own work. If you want more HP then the stock turbo can produce then the cost skyrockets from there. Do searches on here and also Hybridz.org and Zhome.com for more information.

Bleach

I would think that the swap can be done even cheaper than a couple grand. You can use the 280Z's transmission if you want, and the turbo engine sets right down onto the engine mounts. There is basically no money involved in doing the "swap" and no fabrication. If you can hook up all the electrical then you're set to go. The money comes into play if you want to rebuild anything.

I suppose a new exhaust would be in order and a shop can do it much better than most home mechanics.

The swap has been done a lot. The cost of a 280zx turbo varies greatly. They are getting a little harder to find. The cheap ones you find these days vary by what is wrong with them. Hopefully you can find one with major body damage and a good engine. If you buy one with a bad engine for cheap, well then you'll be putting some money into the engine just to get it running first.

Bleach

Yes, it sounds like you've got a good idea what to do. You are correct that you'll need a new clutch/flywheel setup. i think you can use your factory 280Z clutch and flywheel though. It depends on how much power you have though. It may slip, but probably not. The turbo uses a wider contact area, but the flywheel is nearly the same weight... if I remember right. Just more cyntrifical weight.