I would suggest Magenta Research stuff,
I have used their multiview line on several shows.
I will never go back to using normal video cable for anything longer than 50'
- 1920 x 1200 resolution at 2000 ft.(610m)
- 1600 x 1200 resolution at 1500 ft.(457m)
- 2048 x 1536 resolution at 1000 ft. (305m)
http://www.magenta-research.com/overview.htm

I would suggest this transmitter,
http://www.magenta-research.com/brochures/UTx_sheet.pdf

and for the reciever,
http://www.magenta-research.com/broc...000_AK1500.pdf

That will easily get you the distance and resolution you need.

Let me know if you have any questions.
Joshua Wood