Don't know what it is, although it could easily be a Bartlett from the looks of it. Looks like you have some pollination going on already, so maybe there's a pollinator nearby.

I cheated and used a flowering branch from another unknown pear tree and manually pollinated part of the tree and also left the blooming branch in water beneath the tree. Last year (our first year in the house) there were no pears at all.

Any other guesses?

Come back when they're ripe and include a picture of the entire tree and I might have a shot.

From the look of the fruit at this point, and just based on raw statistics, it is most likely a Bartlett. If the tree was planted by a fruit enthusiast, it could be one of dozens of unusual or uncommon varieties that look similar, but then you wouldn't have just one pear tree. But to be sure let Harvestman and others with experience see it at harvest time.
Hope you enjoy your pears!