I read somewhere that Vegas and New York are THE property hotspots for
the next few years. Property is forecast to go through the roof, and
that means that with luck, I can get a house now with a loan that I
can afford, whereas if I wait, it might become out of my price range.

I want to get a buy to let mortgage, with a managed tenancy agreement,
but I keep searching the web and cannot find anything that is such a
mortgage.

It could be a miss translation, maybe you call it something different
in the USA - or maybe you just don't have them. I live in England, but
want to move to Vegas when I

Over here, a "managed tenancy - buy to let mortgage" is where I buy a
house from the Estate Agent, and they find tenants, screen them,
handle all issues (plumbing, maintenance, etc) at a fee that is a
percentage of the rent that they can get.  I earn some off the rental,
and the escalating value of the house is an asset for me too.  For the
Estate Agent (I think you call them Realtors) they take a cut of the
rent for commission, and take a commission on the sale of the house,
and the sale of the mortgage.

The idea being that when I am ready to move to Vegas, I either sell up
the house and buy something else, or give the tenants notice and move
in myself, or buy a house for me separately.

Can you give me some advice on where to go for the sort of deal I
should be looking for? Its just  aquestion of getting the right
terminology I think.

Howdy allwehereisradioga!

The odds are extremely poor that you can find such an
arrangement in the U.S.  It would be a two step process
of first buying the house through real estate agent, and
then getting a rental agent (or property manager) to do
the rest.  Most property managers in the U.S. get a flat
monthly fee instead of a rental percentage, you might find
someone who takes a cut instead.

Hopes this helps!  denco-ga