I own one in edmonton, there is 3 parts guys in town: Mark Iltis4x4, sung iltisparts.ca, (the biggest dealer. he has a warehouse full of parts), and Punchbuggies.com and 2 mechanics. (ken and super dave)
most of the parts on the motor can be found from volkswagen, it is a VW engine, same as a 81-83 rabit except the iltis has a carb instead of fuel injection. Rockauto.com still has lots of parts that fit the engine. The only hard to find parts are breaks, so nurse em and don't burn through them, they can be re-padded for cheap but only if the shoe itself is still good, the drums last for ever, I have a spare set, and after 3 years of driving... my original drums are still like 80%
Plugs, fuel pumps, clutches, Cvs are still being made new as they are the same as many other vehicles.
if you don't want to run the 24volt ignition its not hard to switch over to 12volt and dump a non military distributor in, then a cap costs $6 instead of $40 and plugs are $7 instead of $70, plenty of space to swap the military air filter for a K&N
As far as vehicles go, its cheap to maintain, it doesn't break stuff all the time, Ive spent less in 3 years then what I spent on my ranger in 2 years... and with the iltis, most of the parts can be rebuilt for a fraction of the cost (starters, alternators, carbs, distributors).
The most expensive thing I've had to replace was the tranny, and I bought it ####ed up. Brand new out of a create and installed for a whopping $1700, try getting that price that with any other vehicle.
Ontario and quebec have a lot of iltis kicking about, If I was the OP I would jump on one. a typical up iltis (running, rusty and plated) should be between $3000- 8000 depending on variant, body condition and mechanical, expect to drop $4000 if you want to restore an iltis to like new provided you don't need something big like a motor or tranny and you do your own work (welding, mechanical, electrical)
Im in about $10 000 on this guy including purchase price and custom aluminum doors