You might be right about rip-off merchants, but why don't you offer a link to an Apple Authorised service centre that will sell you the part?
The one's I've dealt with, like AMSYS, MR, Honeylight, etc, will NOT sell just the part, only the part as part of a service job. Which they will charge plenty for, making up the difference.
I think its possible that Apple doesn't want them to sell the parts retail as part of their being officially certified AASP. That's what 3 of them have told me. Your attachment is from the Apple Global Service Exchange, offered only to certified mac techs. They are not supposed to offer those parts for resale.
If you know of one who will sell the part alone, retail, to a normal user, I'd like to known which AASP that is.
well i'm not going to tell you who i work for if thats what you are getting at,(but i'm happy to take orders behind the veil of the internet) that image is from my own gsx account that shows that the part is available for purchase right now. (i blacked out my home address and the account numbers)
In regards to your statement about not selling retail being a requirement by apple that isn't true, AASPs can sell parts just most wont, my company will sell parts every now and then and we aren't a particularly big aasp either.
AMSYS won't as they want at least £50 markup, and will try and slap £70 labour on there as well, I know this because i've worked for them.
but the parts are available, i suggest that the OP ring round a few, i think quite a few will order the part if theres a few quid on top, but you don't need to pay what the bookyard or VIS want for them. (ps: where do you think they get their parts from to sell retail? Hint: from GSX.. why do you think they all have a lead time/backorder on them, its because they'll order them in from gsx to sell them.)
just to clear anything up, ive nothing personal against other AASPs, or the parts companies but there are legit ways to spend less, and the OP should approach all avenues to save money.