I have resenty began to plan a new compain were all of the players are RT. So ido have some ideas but not all of them are there, i did have the idea for a huge race across aplanet or somthing like that, they have been invited by some rulling overlord, somthing like a sheik. And they have to race across the planet sort of like the move Hildalgo, except with more "evil" things .

any ideas to give, please do, along with constructive criticism

A few questions if you would.

1. Why are all the players Rogue Traders? I think representatives from the Navis Nobilitae (House Scion alternate rank for Navigator), a mercenary unit commander (Arch Militant), hotshot pilot (Voidmaster), Rogued Trader (self explanatory), Adeptus Mechanicus liaison (Explorator), Ecclesiarchal Missionary (Missionary) and well outright rich noble (Seneschal) would all be suitable for the situation. If you have only RTs, you'll end up with a very schismatic group and possibly too much infighting.

2. Is the game entirely ground based? As a player of an RT character myself, i rarely leave my ship without a unit of mercs and my personal command staff/bodyguard entourage. It might be tricky to get a group of singular RTs to be on the planet, risking their necks for a mere competition.

3. If the game isn't purely ground based, how are you going to handle starship combat? That many ships would either quickly blow each other apart if infighting occurs, or would wipe the floor with all but a powerful fleet bearing down on them (talking 3+ cruisers plus supporting escorts).

I think the premise you have for the campaign sounds intriguing, but i'd open it up to something more like:

"A planetary governor of an important trade outpost has sent an open invitation to partake in a stellar race to journey to an uncharted star where a great treasure is rumored to reside. the victor will be granted exclusive trade rights and shipyard access at the starports and orbital docking facilities.

The race will be treacherous as it skirts around a region of powerful warp storms and several systems known to be infested with foul xenos, however the reward would greatly benefit your rogue trader's house. Also, who knows what other valuable artifacts may reside at the destination..."

very interesting. this sould end up very suprising to the players. thankyou.

You're welcome.

Ok...if all the players are Rogue Traders then do they each have a ship? What about Starships that have been outfitted with experimental drives and such to be faster and more manevurable. They would race across the galaxy (or just the Expanse, Calixian sector, what have you). The first to arrive and submits to a wide range of tests (well all the ships get tested), is given to keep the upgrades (so long as they work) and the Mechanicum's eternal thanks. Everyone else must pay through the nose or be on a retainer to keep the upgrades. Along the way, they come together somehow to fight this threat or that.

I have not seen Hildago, but watch the Cannonball Run movies for something to what I'm speaking of. These ships in question in this case could be vastly different in builds to check different variations in speed.