When I did a search of the forums using the parameter "content creation contest", this was the only thread which came up, so I decided to bump it, because I think it's a great idea, and nothing seems yet to have come of it.
While my search has been reasonably diligent, I cannot yet say it has been exhaustive, but I have yet to find a high-capacity covered hopper for use in TRS. I'm specifically looking for the a car like the  Trinity 6351 cubic foot, (cf. 
http://www.rrpicturearchives.net/showPicture.aspx?id=885483),  the ARI T6350 (cf. 
http://www.rrpicturearchives.net/showPicture.aspx?id=1645199), the Gunderson 6352 (cf. 
http://www.gbrx.com/PDFtecbulletins/Hopper6352.pdf), or the similar sized car made by National Steel Car. These are cars about 65 feet long, with four bays, specifically designed to handle lighter density agricultural products, sometimes called "distillers dried grains". While all of these are from the contemporary era, back in the 1960's or 1970's, the UP had a quantity (200, I think) of 125 ton cars of similar size, a variant of the Pullman Standard PS-2 design, at least one of which is still in service 
http://www.rrpicturearchives.net/showPicture.aspx?id=149218
So I propose a contest, as follows:
1) Official start date is December 1st; contest will close on 1 February; winner announced 15 February. Eligibility: open to users with a valid User ID in Planet Auran; judges may enter, but will not judge their own submission. 
2) An entry will be one car with gravity unloading for the version of Trainz of the contestant's choice. Multiple entries are permitted, as long as they are not merely re-skins; if two or more entries are submitted by the same contestant for the same version of Trainz, each must be a different car types from the others. If the same car is produced for the "native mode" of multiple versions of Trainz, each is a separate entry.
3) The participant's will submit an asset of the car types listed above, or may create a "free-lance" asset of similar volume (greater than 6200 cubic feet) and characteristics (gravity unloading) to those in the list. Assets submitted may include either hatches or continuous troughs for loading.
3) Bogeys, and couplers will be excluded from judging.
4) Submission will include a basic skin, similar to that in the picture of the ARI T6250, in the participants choice of color.
5) Entries will be by screenshot posted to a thread opened specifically designated for that purpose in the Auran forum, and a ~.cdp files will be sent to a designated address.
6) Prizes? Maybe, to be determined. However, only one prize will be awarded to any contestant, regardless of the number of submissions made.
So, two questions: if this concept is opened, who is interested in entering, and who is interested in judging? I would say that judges are eligible to enter, but will be excluded from judging their own submission.
ns