The bottom of the strut on a 4x4 is 51 mm in diameter. This is a size that is quite common, so you might be able to find other shocks that fit. But you also need to take into account the total length and the stroke of the damper. You don't want the damper to bottom out or the wheel hitting the arch on big bumps.

I have been thinking about using Bilstein inserts for an Escort mk1/2. You can get some strut cases and build your own coilovers that way. But in the end that will be a lot more expensive than getting a pair off the shelf dampers.