I have seen some collected P. halapensis as bonsai but not many.
I tried them for a while but had too much trouble with branches lengthening and little back budding so eventually got rid of them in favour of Japanese Black pines which grow and develop quicker and easier here. Certainly worth trying halapensis in your climate though. You will need to learn how to pinch and prune to make sure the branches do not elongate too much and to make sure you have plenty of shoots along the branches.
The 'Lone Pine' of gallipoli fame was originally thought to have been P. halapensis but the trees grown in Australia from cones collected from the ground after the battle have been identified as the closely related P. brutia (Turkish pine) which used to be classed as a variety or subspecies of P. halapensis. It is possible that these trees (and maybe most of what we call P. halapensis??? in Aust) could be P. brutia - I do not know what differences there are between the 2.
The tree that has been planted at the Lone Pine cemetary on Gallipoli turns out to be P. pinea (stone pine) which probably shows how much alike these species are.
In NZ the trees planted as 'lone pines' are actually P. radiata

and another is a stone pine.