Hi there,
Theoretically you could bring the car to the UK and 'only' use it on private land. You wouldn't have to register it, nor insure it, nor pay the road fund license for it. You 'could' find a suitable insurance policy from a specialist insurer such as Adrian Flux, who I think, will do policies for car collectors and for car shows etc as often people don't want to drive the cars themselves on the UK's public roads.
I'm thinking you have a Porsche 996 from your username - and if you're thinking you'd make a loss (all cars depreciate unless you have something ultra exotic) then you need to compare the loss you think you'll make selling it in the USA with the costs of shipping it here, paying the import duty tax and the 6months parking it up costs (as you will not be allowed to park it on UK public roads.
Just the shipping costs is likely to be around £1500-1800 (USD $3000- 3600)for a sealed container as I paid around £1250+VAT for a open transport method for the F150 I imported from Texas back in 2004. I'm pretty sure you'd be liable for the import duty upon the container landing on UK shores too - that'll depend on the value of the car itself.
However, look at the rules, I think if you take the car out of the UK again within a certain time, you may not be liable for the import duty etc, but of course when you send it to Holland, you'll be liable for whatever the Dutch system is for imported cars. Another thing to remember with Holland, is you pay a tax every year you own the car based on it's 'brand new' price! so if you have a 15 year old car, and it's value has depreciated say to something like 1000 Euro, you still pay the tax on it's original value ! may mean you pay more tax than the cars worth! - that was the case when my mate was living there and of course, it subsequently may have changed in the last few years. Don't forget also you probably will need to do some modifications to it to meet Holland legal requirements and also you may need to do some engine mods to accept the higher octane fuel here in Europe.
Hope the above helps and gives you a start into researching into this
Cheers, DtM! West London & Slough UK!