You could have TLC do a conversion for you if you have an extra $50K laying around, LOL
http://tlc4x4.com/conversions.htm?service=conversion
But they do some siiiick work. These are the same guys that do the ICON's.
From what I remember Slee will install a 2UZFE into an 80 for ~$12K. I saw his 80 at the Adventure Expo a couple of years ago, nice work, factory quality. It looked as though it belonged.
I bought a 2002 2UZFE for my FJ40 H55F project, I paid $500 for it with ECU, harness, fuel pump, etc. It was advertised on Craigslist fairly close to me in the US (I live in Canada). It has, IIRC, documented ~40K miles, and removing the oil pan to convert it to a rear sump, (taken out of a Lexus SC400), revealed the block to be in great shape, crosshatching still in the cylinders.
I've rounded up all the parts I need to make it work, but it wasn't easy. The drive line components to mate an H55F 5 speed/split case with output shaft parking brake to a 2UZ were hard to come by, it took a crazy amount of time to organize, talking to Cruiser Heads and parts vendors all around the world (US, Japan, Australia, even Pakistan!). Going all Toyota was tougher (but satisfied the purist in me) because there are fewer options for conversion kits, adapters, etc. for my chosen route. It isn't a fair comparison because it isn't apples to apples, but it does show you what dedication costs. My 40's parts cost: motor $500, bell housing kit $2000, new factory H55F $2700, used split t-case in good shape $300 and parts to make the drive line park brake work, $400 (obsolete parts are expensive!) - total, $5900.
A V8 conversion in an 80 should go smoother, adapters are more common, but the devil is in the details. Things like wiring and sump locations, motor mount fabrication, transfer case/transmission/drive line choices all have to be made and the costs can add up. Adapters can be expensive if you want to keep the stock transmission. Anything else may introduce other types of variability that depends on the route you go, such as complications in drive line position. Be prepared for conflicts like integration with OEM electrics, such as seemingly small details like getting the tach to work etc.
If I would hazard a guess at the cost of a home done V8 conversion expect to pay a conservative ~$3K to start for a used motor and trans adapter. There will other costs that will go up from there, and of course whatever your time is worth too. The upside is that you will know your rig's inner workings intimately.
I'd love a 2UZFE in my LX, but for more power I'm going with the factory TRD supercharger for the above mentioned reasons, besides I'll be busy with my 40. I'm tweaking my LX, but I'm trying to limit mods to the tried and true "plug and play" bolt on variety for simplicity's sake.
Search the forums and invest the time to read so you know what you're up against. There are enough Chevy and a few 2UZFE swaps out there now, many well documented here on 'Mud.