We have 5 clients coming to New York ( 11 Sept-13 Sept) and Los Angelas ( 15-17 Sept. )

We want to hire a good guide who can also drive them in these 2 cities. These people want to have a quite flexible schedule. And somebody really knows very well the city, can recommend good local restaurants, tell the history of the tourism spot etc. It can be 2 different guides in these cities.

I contact some travel agencies, none of them accept this kind of personalized trip.

Anyone knows any agency could do this kind of job. Any help is appreciated.

You really don't want a guide with a car in NYC. Traffic is horrendous and the passengers will sit in traffic all day. And besides paying for a car and guide they will have to waste time and money continually putting the car in and out of a garage at $30 a pop.

If you really want to arrange this suggest you contact the NYC Convention & Visitors Bureau. They will have info on costs of private guides. Perhaps a guide plus a driver is what they need - one to deal with the car and the other to guide the vacationers at the various stops.

Do the passengers all speak fluent English - or does the guide need to speak another language as well?

You can hire a driver in NYC and LA from Execucar, a corporate car service company. It's wildly expensive, but this service does not include a guide, just a driver. You'd have to book a guide separately, and to be honest, I can't imagine who would do this kind of thing, so I can't make a personal recommendation. Private tour guides are just not the kind of thing people have in NYC for the most part.

In NYC at least, I think your clients would have more fun exploring the city on your own by subway and by foot. But if they are the kinds of people who don't like to do anything for themselves, that might not be the best option.

There are really high-end travel agencies that can arrange anything for people for whom price is no object, but I don't know much about those.

There's probably a better option. If they are staying at high-end hotels, then the concierge at the hotel can and s should make these arrangements. Luxury hotels who are used to dealing with big-shot guests can provide both cars and guides in both cities.

There is a Guides Association of New York that might be a good starting point. I can't vouch for the organization or its members, but you can at least start getting an idea as to tour options, cost, etc. The NYC Department of Consumer Affairs grants licenses. I know someone who used to be a guide specializing in very high end opera-related tours in NY and elsewhere - there must guides who focus on other specialized interests or general sight-seeing/city info types of tours.
Good idea mentioned above to also check with hotel concierges.

I can't vouch for the OP. These kind of requests are scams. Usually they are sent by email. This guide is ignoring the request.

Thanks everybody. I convinced my boss just to hire driver for them. Actually the clients are not that intellectual, they just want to be showed the tourism spot in NY and LA and take pictures so just driver should be fine.

Anyone who knows good car rental company with drivers? Yes, clients speak fluently English. But my boss want very professional driver, with uniform, very helpful and nice...

Thanks again for your suggestions!

They will have a lot of trouble taking pics form inside cars and you can't just stop cars at the biggest tourist sights - NYC has practically no parking on the street - and I think these people will be very disappointed.

But - it's your dime. Try googling limousine companies - not car services like Carmel or Dial7. You should expect rates starting at about $125 per hour for a basic stretch limo - with higher rates for limos with TVs, beverages, etc. Also the driver should be tipped 20% of the total price. So, for an 8 hour day expect at least $1200. And it will have to paid in advance by credit card.