I haven't seen anyone else use this build, but i've had quite the nice success with it when we need more AD and tanky (i.e. if the entire team choses AP casters)
frozen mallet, beserker,s greaves, hexdrinker, sanguine blade, wit's end and stark's fervor.
the shield procs a lot with the attack speed and I do pretty decent damage. I get a good enough amount of magic resist too.Ii don't get much trouble from AD carries(shield), but I think AD casters would screw me over though (haven't faced them much yet I think).
I don't rely on heartseeker strike for damage, but the passive seals the deal most of the time. I harass with it from the end of it's range as well as the spear toss. Often times I actually do finish an enemy off with it if they manage to start escaping and spear is on cooldown.
for runes I use armour, magic resist and crit chance and crit chance quints. I go 9-21-0 for masteries.
edit: title's typo *Pantheon, but I guess the pen is mightier than the sword.