this would be a really stupid rule. To pod lower system players mustn't result in a penalty. What you could implement is sth like a reputation. Therefore the system looks "who shot first", "which player got what ship", "how long did the player with the better ship wait until shooting back", "who was podded". If there's a "Normal" PvP with 2 Gemini-Ships, the winner of the battle will gain reputation. The loser won't lose or gain reputation.
Other thing is, if a Gemini-player fights against a Sol-player. If the Sol-player shot first, killed with one hit, he will LOSE reputation. The Gemini-player won't lose reputation. If the Gemini-player wins, he will gain reputation, more than if he would fight against another Gemini-ship. The loser, so the Sol-player, won't lose or gain rep.
What does the reputation show? It shows, how "fair" the player is. Does he shoot many low levels with a bigger ship? If yes, he will have only few reputation. Is he a fair player, does he wait, if he is attacked by lower levels? Does he only fight against same equipment? If yes, he will have a high reputation, so everyone will see, he respects players etc.pp.
Facts:
Only the winner gain/lose reputation, loser won't gain/lose anything. Winner can lose or gain reputation, depending on the situation. How many people fight, which ships, which tech-level, etc.pp.
You spoke about being attacked by clanmates with higher tech, because you defended against another player. This happened to me once, and if i see one of them, i'll GET them, if i have the good equipment for it. No matter, whether it's a lot bigger ship ^^.
Greetings
Silverman