I haven't found this anywhere on the site (but then again, I'm new around here, so I might've missed it), so I thought, let's just make a decent post about it.
It is possible to give upgrades (no weapon/armor/shields/scarabs) and technologies to players without the need of having to research them in the proper building.
For example, let's say we want anyone on Force 1 to receive U-238 Shells and Stimpacks when they bring a Marine to 'Levelup Beacon' and Ocular Implants, Moebius Reactor, Personnel Cloaking and Lockdown when they bring a Ghost to 'Levelup Beacon'. You can change the conditions to anything you like.
First, place a Marine and a Ghost somewhere on an unused part of the map, and give them to a Computer or Neutral player. (player 9-12 work okay for this, but the triggers are a little difficult to write. I'm gonna assume you use player 8.) Draw a location over it and call it 'Give Upgrades'.
Second, make sure the upgrades and technologies are enabled for everyone on Force 1 and researched for player 8.
Third, create the following triggers to give units to the current player. Any special upgrades and technologies will be given along with the unit. Make it like:
| Trigger |
| Players: |
| ¤ Force 1 |
| Conditions: |
| ¤ Current player brings at least 1 Terran Marine to 'Levelup Beacon'. |
| Actions: |
| ¤ Give 1 Terran Marine owned by player 8 at 'Give Upgrades' to current player. |
| Trigger |
| Players: |
| ¤ Force 1 |
| Conditions: |
| ¤ Current player brings at least 1 Terran Ghost to 'Levelup Beacon'. |
| Actions: |
| ¤ Give 1 Terran Ghost owned by player 8 at 'Give Upgrades' to current player. |
Then you want the units to return under player 8's control afterwards:
| Trigger |
| Players: |
| ¤ Force 1 |
| Conditions: |
| ¤ Current player brings at least 1 Any Unit to 'Give Upgrades'. |
| Actions: |
¤ Give all Any Unit owned by current player at 'Give Upgrades' to player 8.
|
| ¤ Preserve trigger. |
There, all set. You might want to add a kill score requirement to the 1st triggers, or change the requirements into something completely different. The last trigger does not need requirement adjustments, since it won't activate until after one of the other triggers activated.
Also, you might want to give only some of the upgrades (U-238 Shells), and give the rest of the upgrades at another beacon (Stimpacks). Then simply use 2 neutral players (each with it's own units and location). Player 7 starts with U-238 Shells researched. Player 8 starts with Stimpacks researched. The upgrade you receive depends on the player from which you receive the unit.
Note, any upgrade/technology that is not researched for player 8 should be disabled. Otherwise, when players give their unit back to player 8, player 8 might receive an upgrade, and then pass the upgrade along to other players.
EDIT: Forgot to mention. If you use a computer player and have more than 1 unit at the location, you need to make all the units invulnerable. You might want to make all of them invulnerable anyhow, just to be sure. Also, if you use a computer player (not a problem with neutral players), make sure units like the overlord don't leave the location at the start of the map.