First, you asked about a long bar. How long are you thinking? What is the approximate diameter of the trees you'll be working with? That's one of the biggest things that will feed into how big of a saw you will NEED to take down those trees.
Clearing trees means long days of hard work. Its one thing to go spend a few hours cutting a truckload of firewood. For stuff like that, almost any saw will work. When you're going to be working at it all day long, that's when the pro-saws (more power, less weight) are worth the extra money, and an MS261 is a great pro-saw to start on. That said, $1400 USD is WAY WAY WAY too much money to put into any 50cc saw. At that price point, you're almost into a new 70cc to 90cc saw.
Honestly, if you can find an MS261 that's seen light to moderate use, there's no reason not to that route and save a little more money. The classifieds adds on this forum has probably been the BEST source for used saws I've ever come across. I bought my 026, and both of my 036 saws used (many years ago) for less than $300 each (only the 026 was from this forum), but (as you've said) most people want a mint for their worn out old pro-saws which is what pushes me towards the clones.
You'll get a lot of opinions on here about the Chinese clones. I have a G660, and absolutely love it. I run a 28" bar on it most of the time, and I have a 41" bar that I've had to use on a couple of trees including a LARGE red oak that died in my yard. With that said, if you buy a clone you WILL need to work on it before you even start the saw. Once the necessary upgrades are completed, they are a very cost effective option for someone that only needs one for limited use.
One other think to think about is that felling the tree is, by far, the most dangerous part of the process, and the more things there are for the tree to get hung up on, hit on the way down, or land on, the more tricky it becomes. Depending on how things are on this property, it might be worth having someone someone else get them on the ground for you. A trip to the ER gets expensive, and coffins ain't cheap either.