I think most used gear outlets will generally pay you about half of the price at which they expect to sell it. If this sounds low, keep in mind their overhead plus the fact that if their customer returns it as defective, the dealer doesn't return it to you for refund.
Completed auctions are a good indicator with 2 caveats: 1) it's very much dependent on the completeness of the description and the history of the seller and 2) it's very dependent on geography (especially for the expensive-to-ship monorail).
In general, monorail cameras don't seem to sell well - at least compared to field or technical cameras. Don't ignore the value of accessories, such as bag bellows and lensboards.
But - and this is just my personal opinion (as if the above wasn't personal opinion) - I would look at this somewhat delicate equipment all in a plastic crate with no padding or separation and question how it was cared for. Just my 2 cents.