For the past year or so, the weekend gaming group I am a part of has been having a great deal of fun playing Lunch Money (with both expansions) with seven card hands.
This gives room to:
Accumulate a bit of defense;
Hold onto some health to use later;
Build up a sweet attack combo over a number of turns;
Abandonment can be truly devastating, (Or replace a worthless hand with a killer.)
Turtling:
Discard and replace 2 cards free of charge.
Pay one coin for each additional card discarded and replaced. May not spend last coin, even with healing cards in hand.
Hide:
Heal, discard and replace as many cards as desired without cost. (As per basic rules)
We've found that 7 cards makes for some truly epic battles, and it seems to work well (for both offense and defense) whatever the play style: "Tall poppy", "Blood in the water", "Cutthroat", and even "Everybody hates me".
Has anyone else tried something like this?
Hi Black Betty;
Our gang frequently plays with what we call "Competitive Discard Rules." I'm not sure if that's a "thing," but here are how our rules work:
Players may turtle as many cards as they have conscious opponents, with the exception of the first round, when they may turtle all 5. [Note: we call turtling all 5 a "Gamara" after the mighty terrapin of Godzilla fame].
Players may turtle more than the number of conscious opponents at the cost of 1 counter/card (however their hand cannot exceed 5 cards).
Example: if you have 3 opponents, you may turtle 3 cards free-of-charge. If you want to pull a Gamara (turtle all 5), it will cost you 2 counters (5 cards - 3 opponents = 2 counters)
Players may turtle all cards while Hiding at no expense.
Note: if you're playing with a small group, dropping someone into Time Out on the first round essentially prevents her from pulling a Gamara, which can be a devious move worthy of future retaliation.
As you might imagine, this can make the end game VERY tactical, as your ability to turtle cards and garner defense becomes more and more difficult (one card turtles only-- or pay!)
Another rule we enjoy and enforce with glee is the "Sorry Rule." Simply put: any player saying "Sorry" in an apologetic manner pays a counter. (We DO allow mediation to determine if the sorry was sarcastic or not) This encourages the take-no-prisoners aspect of Lunch Money and desensitize newbies 
Trust me: the hard, nitty-gritty blacktop world of a Lunch Money throw-down is momentarily all pigtails and butterflies when you watch an opponent knock herself unconscious by apologizing. It's perhaps the most humiliating a pathetic way to get knocked out of the game, and the most entertaining for your opponents. 
Something about how fun it is pulling the wings off flies and microwaving the neighbors cat?