In the current market it will never happen
Why not start a thread for expressions of interest as a number of guys will probably be interested in some if not all of what you have.
I can see where your coming from wanting rid of the lot at once but i dont think anybody would part with 15k.
For an indivdual to buy the lot unless their local to you they have a huge logistics (read transport) issue.
Best you could hope for is pledges from people to buy certain items at an agreed price (your total target being 15 -20k )
no deal is finalised until your target is met .
Interested parties make you an offer for what ever , you can accept , decline or negotiate a better price or throw in more items for the same price . When a price is agreed buyer pays you a deposit of $50.00 $100.00 or 5 % of price , this is non refundable if buyer renegs on deal but refundable if you dont reach total target .
Obviously a time frame would have to be set (maybe 3 months ) you dont limit the deal to forum members but its a good advertising tool (would be the decent thing to do to donate a % to Graeme for use of the forum).
What this system does is frees you up to accept possibly less for individual bikes items than you believe they are worth as you are only trying to raise a predetermined target.
You dont have to go public with what each item is selling or has sold for or even disclose your target.
This is a rough draft of an idea that may or may not work , Its a trust and risk Scheme and will invole a bit of work on your part. Frosty has already indicated he could be keen on the NOS PE stuff so sign him up and take a deposit , your 2k towards your target and 3 months to go.
You have a good selection for sale there , key is dont be greedy and if after 3 months you have not reached your target then return the deposits or if your happy at that point honour the deals and ebay the rest at no reserve.