So I'm looking at the racial stats and trying to figure something out - assuming that you are building to the strengths of the race (i.e., using primarily the stats they are good at so that limited stats have little to no impact on your character), is there any build you can do with an ork that a troll wouldn't be better suited for? I keep looking at the ork and think there must be some advantage I'm missing.

What campaign/module are we talking about? They all have different Karma celling and thus things vary drasticly.
For low-karma campaigns their maximums don't really matter - only start bonuses do (unless you go for highly specialized build).
Now, here's what we have for high karma situation:
-Trolls are subpar shamans, riggers and deckers. That being said they can be all these things - it's just better for them to rely on some sort of martial prowess instead of their craft. Orks aren't the top of the top people for this matter either, but they are more than able to specialize on these crafts having some weapon proficiency just as a back-up. So where ork could be, say, a shaman with a bit of double-barrel-unloading, troll could only be a double-barrel-unloading with a bit of shaman flavor.
-Trolls are also the worst faces in the game having the lowest three etiquette to gather. Orks stand alongside humans and dwarfs on this one.
-While they both make for probably the easiest street sammys, trolls are a bit more hinged towards melee/thrown weapons, while orks have 1 more quickness at max thus being better shots and having the access to the highest abilities for ranged weapons.
-They both are good at taking punishment, but trolls are obviosly betters.
-With the two points in body and one in strength, trolls are the fastest way to become chromed-up monstrosity (if we are talking Hong-Kong here, otherwise they are as good at it as any other).
-They both are just as good at being mages and adepts as anyone else sans dwarfs. So yeah... A bullet-spongy troll throwing mana-balls can be on the menu.

Well, I've played through DMS and DF, and was just getting started in HK. In both DM sand DF, I don't think I had any character ever raise a stat above 7. This is partly what I was referring to when I mentioned "building to the strengths of the race", in that I'd focus on builds where the only stats that may go significantly high would be stats with a higher limit for either race, and stats with low limits would either go unused or only be dipped for a few points, and so the limits would really not be an issue. So as you say, only the start bonuses really matter, and this is why I was questioning the value of the ork. The troll gets +1 Body and +1 Strength, while the ork only gets +1 Body, and the only drawback on the Troll is lower maximums in stats that (if building to strengths) are never really a factor. So if maximums don't matter, it just seems that the extra strength bonus for the troll makes it categorically better than the ork.

And yes, there are some things an ork can do that a troll would not be as good at, but for each of these there are other races that would clearly be better than either the ork or troll. So perhaps it would be better to say that there is nothing an ork can do for which there is not another race that can do it better. Would this be accurate? Or am I missing some skill or quality of the ork that would make it in some way favorable over all other races in a particular role?

As far as I can tell, orks are just a subpar race in this game, with no tangible advantage over any of the other player races. So other than RP reasons, is there any justification for playing an ork?

If you ask what you are missing, to an idiot like me it seems you are missing a sense of role-play. I don't think this is a fault. Some prefer to play a role and some prefer more like a wargame.

Hence the caveat in my question:

I don't know if it's included in the game, but in the tabletop version of the game at least, trolls have to pay more for their equipment due to size and shape issues.

This kind of comes into play during missions - there are cases where you cannot find the correct size uniform if you're a troll. However, I believe this also affects the dwarf in practically the same way (albeit the sizes are too big instead of too small).

That said, the instances where this happens are very few - at least in the official campaigns.

In shops, no races appear to be disadvantaged one way or another - everything always fits for all races at the same price. It would have been kind of cool (or possibly annoying?) if there had been more racial differences with respect to equipment purchases.

Well, yeah. Orcs are basicly humans with one less karma plus it's fixed at the body.
However:
1)HK is more karma-intensive than DF: you probably will have far more problems with nuen other than with not being of appropriate skill to use shiny new toy.
2)Talking your way past people became more important with HBS trying to implement this whole "face" business, so that charisma celling will collide with troll unless you really know what to do and when, or wish to wade through a bloodbath.
3)So the orcs are probably better if you're trying to build this sort of shooty/stabby but persuasive action hero type-of thing. Or just more sturdy shaman than his/her peers.
4)But overall, yeah, trolls will take orc jobs without breaking a sweat. And those humanis cronies thought they were in trouble! I, personally, would love to see the equipment system being reworked at least to some degree in next installment (should it be coming). I really dislike this whole tiered system. And drones. What fun it is not being able to create your own steel friend from junk and customize afterwards?