Are there any games/tactics where infestor controlled units are used to build "foreign" units?

Solution 1:

I did see one game commentated by Husky where a Zerg player captured an SCV which was sent to repair a tank on the battlefield, and he did work up the Terran tech tree. But I think that game was really just for fun as many bizarre things happened, and the players goofed around more than actually playing to win (maybe someone remembers that one and can give a link?). I have never seen anywhere else where neural parasite was used like this in a legitimate game.

I would say this is not feasible in a legitimate game because:

1. The amount of infestor energy required to pull this off would be probably be better spent elsewhere. You need to escort the worker via parasite back to your base, then throughout construction of the building. OTOH, parasiting a probe is easiest because a Nexus warps in instantly.
2. It will take a long time to get to a point where this is even possible. By this time, you won't benefit much from the other race's low-tier units & structures. If it were hypothetically possible in the early game, I could see a benefit to using terran supply depots for a wall-off, or getting quick marines for anti-air.
3. The APM required to efficiently use this tactic again would probably be better spent elsewhere. This is not a tactic you will ever bother practicing, so if you actually do this, you will be basically treading in unknown waters throwing off your natural rhythm. How will you hotkey your new command center or barracks for example?
4. If your creep spreading is what it should be, then your options are limited for building placement. As Terran at least you could head to an island as a workaround.

There are lots of low-tier "foreign" abilities that could possibly be practical though, if you get really lucky and manage to pull this off:

2. Chrono boost on Zerg upgrades or larva
3. Marine + roach or muta army composition
4. Scanner sweep / MULEs
5. Missile turrets
6. Planetary fortresses
7. Bunkers for roaches / hydras

Though most of these are still not going to be practical if you have any creep spreading.

In 2v2 I have always wondered though if allys have used this tactic. It would be MUCH more feasible here because:

1. You could build your 2nd race base amongst your ally, avoiding creep
2. You don't need to bother keeping a hold of the worker with neural parasite as much. If your ally is Protoss, it would just take 1 neural parasite.
3. Creep spread tends to be more conservative in team games unless your ally is also Zerg.

But in a team game of course it's also less compelling because you already get the army composition. The biggest benefit would be chrono boost, or sharing transports. I won't mention "less communication required between teammates" because well, you should just aim to improve the communication, not work around it :)

But I have never heard even a mention of doing this amongst allys in a team game; maybe you cannot neural parasite an ally?

Solution 2:

Destiny used an Infestor to build a Nexus in a ZvP (Grandmaster ladder game). There's a replay and a VOD available, in the video the match starts at around 01:11:00, Infestor-Probe-capturing at around 01:29:00 where the Protoss throws away probes to free up supply.

While the APM is mostly used elsewhere, the Zerg player still manages to tech up to a mothership and using chrono-boost to speed up upgrades (both protoss- and zerg upgrades).

This does show that while this is still gimmicky and extremely hard to pull off, it can be quite beneficial to the Zerg player. Since you cannot be sure to capture a probe in every game, it would be foolish to build on such a strategy. Although it might be another reason to research neural parasite in the later stages of the game.