First of all the Linux App Store may or may not happen (http://www.desktoplinux.com/news/NS7312694782.html) however, if it does the following is something I would like to see implemented.
GNU/Linux Monetary Support:
Add a donation option tab. This tab could be turned off in preferences, and should be unobtrusive, no asking or reminders to donate. Different options to donate: such as a general donation and specific donation. General donations would be shared with the distribution the user is using, kernel/hardware development, and a general fund for software. General software fund: App Store/Software Management would track the number of times each application is installed. (But not who installs it.) Funds could be appropriated accordingly. Each developer would have the option of receiving funds for their apps, or sending the money to another free software or open source project. These funds would not be a reward for past development but to ensure future development. If a developer does not want to participate, their share could be divided amongst the rest. Specific donations could be made to the disto, kernel, hardware, driver, or app developer of choice.
This same option could also be implemented into the software managers of individual distributions.
Like it or not, money is needed to get solid development of apps in Linux! For example look at what Canonical has done with Ubuntu...