I searched and found nothing, can you swap 4motion from a B5 wagon into a fwd B5 wagon? Assuming you have a donor car...... time not an issue, money comes in time.
Least amout of time and money= go buy the car with 4Motion. Easier to swap everything else over to the 4Motion.
2004 Passat 4Mo, 1.8T, stick
past: '96 Audi S6, forced to sell, F. U. nh emissions
'87 VW Quantum syncro wagon, got me into quattro
'85 VW GTI , 17 yrs and 280k miles, rusted away
Long answer, anything is possible with enough time and money, but in this case you'd have to be a masochist. It's not just swapping components; you actually have to cut and re-weld the lower rear section of the unibody from the donor car to the recipient. It's been done (once, that I know of) but in the end you spend a lot of money and hundreds of hours to create something you could pick up at any used car lot.
Better to spend your time on something new, like an amphibious Passat or a flying one.
I have a fwd passat v6 stick and i always wanted a 4 motion but you cant ever find one and if you do its in really bad shape. I had a dream of making that one day too, but the process seems so long. Its probably really is easier to just get a 4 motion passat and just make everything nice inside out.
Just go buy one. If you really want one, it'll take some searching for. I bought my black on black w8 4motion 6 speed from a lady 8 hours away. There's less than 60 of those in North America, if I can just to happen to come across that, you should be able to find any other 4motion.