reddit user Xovaan has created a series of awesome Dilbert-ified TF2 characters:

Dilbert Medic:

Alice Demoman:

Dogbert Spy:

World's Smartest Garbageman Engineer:

Loud Howard Scout:

Elbonian Soldier:

Pointy-haired Boss Heavy:

Wally Sniper:

Catbert Pyro:

They're hosted here, with Xovaan's permission, for posterity since the original images were posted to Imgur where they will eventually expire. Each image links to the original full sized version.

The original reddit threads are, in chronological order, oldest first:

• Dilbert as the Medic didn't exist so I decided to put this together in Photoshop for some reason
• You guys liked Dilbert Medic, so here's Demoman Alice. I don't even know anymore.
• Dilbert the Medic, Alice the Demoman. The next installment: Dogbert the Spy.
• Alice Demo, Dilbert Medic, and Dogbert Spy, SAY HELLO TO LOUD HOWARD SCOUT
• I solve practical problems. Dilbert's practical problems. Here's World's Smartest Garbageman the Engineer
• It costs $400,000 to fund this department for twelve seconds. You requested it: Pointy Haired Boss Heavy (Office '97 Clipart Edition) and a bonus Elbonian Soldier!
• They're finally done. The cast of TF2 recreated as Dilbert characters– with a bonus special guest!
• Hey r/gaming, I recreated the cast of Team Fortress 2 as Dilbert characters and r/tf2 said you might want to see