Custom stock market portfolio module

Looking for a module for a "fantasy" stock market area on our site. We have the StockAPI and other related modules installed already. This is more of a database and administration set-up in Drupal with MYSQL.

Budget: Entertaining quotes from $500-$1,000

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Users can create portfolio nodes. Trading portfolio must include ability to buy and short stocks as well as set limit orders.

Contests:
Admins or superusers can set-up stock market contests

Portfolios for this are separate from their personal user portfolios

Contests parameters include: start time, end time, amount to invest, private/public contests, contests by groups (use existing OG module)

There should be a ranking/review page where contest leader boards are shown

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You may and probably should build off existing Drupal modules Stock and StockAPI, both of which are already installed and working on our system. Hardest part of this code will be "delaying" buys and sells of users so that the 20-minute delay of the yahoo quotes are matched (to prevent cheating from those who have real time quotes).