Steel Cable: True (everything else I tried was cut by the anchor far before its max pull (tried two types of nylon, no Dyneema / Spectra on hand)
W/ steel, pulling it through won't work due to the need for ferrule and stops. Any "hook" could fall off prematurely (ugh!)
I'd much rather work out a very-high percentile retrieval system.
I agree - brute strength retrieval is iffy. It is possible to get these things stuck so good that even the cable would break if you were to use a lever to get it out...
I think a "two cable" system is in order - one cable is the fastener and the second is the retrieval cable. The retrieval cable is on an end so it pulls the anchor out "feet first" or "head first" - but making it so this doesn't get in the way of the initial drive in may be an issue. Assembly can be an issue. Durability can be an issue... lots of issues to balance... Keep thinking (so will I)