I think if this could be done then it should be a Fly Shop that does it. Not the likes of Cash Crusaders (no offence). After all you do someone educated enough in FF who can value the goods properly.

I understand the objective but should I assume for example my Orvis rod that I imported for R2K which sells for R5K in SA mean that I will get valuation on the true value or local value?

Second question is regards to vintage items or similiar/custom items which actually increases in value. Would there be different criteria involved for this?
It is a good idea but I can't really see it working effectively in the long run.

I know of an online shop in the States that does an upgrade service but I've steered away because it becomes vague when trying to sepperate the brand new from the demo and used.