You will probably have to get this on special order from a wood yard as not all makes of large press MDF are 10x5, Medite do this size but a lot of others are 10x4, the usual stocked size is 8x4.
If you go for melamine such as Egger then the large sheets are usually 2800x2070, not one for the roof rack weigh about 80kg but the weight will help stop you taking off
You will be better looking for your lacal panel supplier rather than a wood yard.
the reason I want it is because Im going to build a fake decorative chimney breast in the lounge and it needs to be 5 ft wide exactly to sink my plasma into. standard 8ft x 4ft just wont be quite wide enough
Maybe P/B on a studding framework would work best then - it would certainly be easier to do than 10 x 4 MDF sheets (which might be a bit difficult to get through your front door and down the hallway), and you can joint plasterboard by scrimming, skimming and sanding
There is a reason why plasterboard and other wall lining materials are 4ft (120mm). Its to do with flexibility and robustness. If you intend to fit a plasma screen into the middle of a 5ft wall span you are best using 2 standard wall boards with studwork behind them. There's no way that I would consider inserting an expensive plasma screen into the middle of a 5 ft board. The best way is the hard way.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local