Okay... the answers.

Budiansky's US #17 (Return To Cybertron Part One: The Smeting Pool) introduced seven 'made up' Transformers:

Ferak
Wheezel
Scrounge
Telus
Rotorbolt
Spanner and
Lord Straxus (who?)

Furman's UK #245 (Underworld!) also introduced seven:

Subsea
Warhead
Slayride
Smeltdown
Rotgut
Jackhammer and
Flattop (obviously a Flattop toy exists, but let's face it - it's not him.)

The most 'made up' characters in a Marvel 'comic' were in Furman's 'The Magnificent Six' from 1990-91 UK Annual (but I'm not sure it counts as a comic since it's a text story with illustrations.)

Stampede
Megadeth
Pounder
Claw
Switchblade
Ripsnorter
Backfire and
Steamhammer (no, not the one from Energon).

Since nobody got it, the next question is open to the floor.