It indeed is quite hard to find, which is why I've found myself in these forums. As far as maintaining is concerned, true it might be hard to maintain, but I've kept 2 vehicles with the tri-star badge till now and have come to the conclusion that while you may certainly will have to spend more, you just have to know what you're doing, what's to be done and how rather than leaving it all up to your mechanic or worse someone who doesn't deal with such vehicles in the first place.
I actually can but I already have a W140. The 'baby benz' really is the ideal Mercedes for Pakistan considering it's outstanding durability and reliability yes, but nothing can beat the timeless piece of design and engineering that is the W126.