We've had this question before and I'm afraid nobody has been able to answer it. From UAE there are several crossings into Oman, so there is a chance that if they inspect your car and turn you back you may be able to cross at another point. The borders are quite busy, so you might slip through. If you intend to come back from Yemen the checks there are very thorough. They made me unpack almost every bit of luggage.
Don't even think about trying to bribe anybody in Oman.
Your chances of getting any type of visa for Saudi are very close to zero, unless you are going to work there.