My brother -in-law is selling his collection... ConRad-Norscot-yada,yada. pretty much all 1/50, I think he said he's got around $10,000 into it, can't imagine anyone spending that much, but hey!! Have any idea where would be a good place to sell besides ebay?
I use to operate heavy equipment for 14 yrs so I have quite a few front end loaders, forklifts, and even some farm equipment. Cable cranes on tracks seem to be lacking out there but Hot Wheels does have a truck crane with BW's out there that I have. And of course there are hydraulic machines out there.
I have HW and MB construction equipment. I even have a few from Majorette. As to where you could sell them? flea markets or EBay are the only places I can think of right off hand. Maybe a Pawn shop? Some are buying HW around here. You might try an Antique shop.
Sorry I couldn't be of more help.