DEVELOPERS need a custom theme, will dontate!

I have been experimenting with wordpress and themes a lot recently, but i cannot find anything that fits what i need, so im hoping that a developer can create what i need in exchange for a donation (amount to be agreed before work starts). the website is for a non-profit organisation, that gives young people the chance to enter the media and journalism market by writing articles. the website is looked at by 1000s of people as a source of information and a few of the writers have been given their first proper jobs at newpapers and magazines as writers!

how the site is organised:
there are currently 12 main catagories of posts, within each of those catagories there can be anywhere from 3 to 10 sub-catagories. each catagory has its own menu entry.

what we need:

MAIN PAGE
basically the website needs to consist of a header, a place for a banner advert and a menu on the top of the page. the main part of the page needs to have a square/grid layout (similar to the ‘threat to creativity’ theme by maxisnow) which will display the most recent articles to be published. ideally we want each square to e assigned to each catagory, but this isnt essential. the side bar needs to have a search function, archives, twitter feed and a facebook feed, as well as space for at least 2 adverts.

CATAGORY PAGE
each main catagory has its own page, which is displayed on the menu. this will take the user to a page similar to the home page, but only displaying posts from that catagory.

POST PAGE
each post page just needs to display the article in on the page, ideally with some kind of auto-generated date stamps, and who wrote the article (each writer has their own account). multiple images currently feature in each article, but we want to expand and be able to use video and streaming audio too.

NOTE ON ADVERTS
we have some sponsers, who wither donate money, or provide competition prizes or special events in exchange for advertising. we also have recently added amazon banner adds, to try to help cover our admin costs. the company employs 1 person part time, who oversees everything, and other staff are either volenteers or hired on a casual basis. i am hoping to take over some of the back end management of the website, and manage the website as a whole, while the current person employed will manage the articles and the printed version.

the donation will have to be negotiated. i have no idea what the going rate is for a custom theme. i would be willing to include some information on the developer in the ‘about us’ section of the website, with links to your page and email if you wish or maybe an advert for you (please not this might not be possible). i do not have the authority to approve any donations or have control over advertising, so the negotaion process may take a little time.

if anyone can help with all or parts of this then please reply to this thread and let me know how you can help!