Keeping it in the pot is a good start.

How small is small?

I've got seedlings that are still less then 6ft in their 3rd year.... It takes awhile to get big.

You can use a few methods...pruning of course, you can use branch bended, you can just cut the roots around the perimeter of the tree (read up on that...sounds interesting)... My Seckel is about 14ft tall or so and its going on 7 years old.

Summer pruning once the tree reaches the desired size will do the trick, and of course, as mentioned above the pot itself is a very important limiter.

Well the plan is to put it in the ground. And I don't have a problem keeping it pruned to maintain a small tree as long as it won't harm the tree. I have a few other trees but I am keeping them all at a height I can reach any fruit on the tree. They are all on sd root stock except one dwarf tree. This one came and it's a standard (no idea the variety) and I'd like to still keep it but keep it small. I do not want a 30 foot tree. I'm getting braver at pruning so I'm trying a few new things. I recently severe pruned a mulberry that would otherwise need be removed. We will still need to see how that goes.

Once it hits the desired height top it mid august , or it's done growing for the year and everything is woodified. Lignified? It's early... I hear my coffee dripping but don't smell it yet...

Fruiting itself is dwarfing, so if tree is fruiting while in the pot it is more likely to stay small based on this, even when subsequently placed in the ground.

Pear tree varieties that fruit young are bound to be easier to keep small and fruitful than varieties that are not precocious. Pear trees (and most fruit trees in general) with branches of much smaller diameter than the trunk at point of attachment are likely to be more fruitful and less vegetative (vigorous).

Along with relative diameter, branch angle is also important. Espaliers often are of a design that maintains 90 degree angles of scaffolds. Traditionally they are maintained primarily with summer pruning.

I am not at all knowledgeable about the kind of summer pruning proscribed by DWN, but keeping a tree fruitful with summer pruning has to depend on what kind of pruning you are doing. Different species and varieties also react differently to same methods.

It's easy to keep a tree small. Small and fruitful is a different matter with a pear. In that regard the variety makes a huge difference. Something like Harrow sweet that's very precocious will be easy to keep small and fruitful. With a variety like Comice or Bosc that often takes 7-10 years to fruit, then you need to know how to prune or it may never fruit.

As others mentioned a tree in a pot is only going to get so big no matter what. The tree size will be limited by lack of water.