Here's a quick list of suggestions for you, some maybe impossible so just ignore me if they are :P
1. (F2P) Guild Miner, seen a lot of requests, also seen a lot of people claiming to be doing it.
2. (P2P) Sorceress' Garden, the mini game in which you have to dodge the guards, and either pick up the herbs or the fruit, I have an account useable for this, with added support like the broomstick and things like that, not sure what you'd need though.
3. (P2P) Tuna Potatoes, an amazing way to make money, reqs 68 cooking. An idea for this script could be to possibly run a continuous loop, seeing as bowls are incredible hard to stock up on and the combined ingredients hardly ever buy off the G.E (In my experience).
Script 3 Idea:
Step 1: Add Tuna to Bowl (Chopped Tuna)
Step 2: Add Cooked Sweetcorn to Chopped Tuna (Tuna and Corn)
Step 3: Add Tuna and Corn to Potato with Butter (Tuna Potato) + (Bowl)
Step 4: Repeat
The idea being, obviously with bowls being a really gay item to have to buy/make, you could do it in stages, have a ratio of 1, 25, 25, 25 (Bowl, Tuna, Chopped Sweetcorn, Potato with Butter)
How feasible do you think those ideas are, hope they tick some cogs to some people :)
EDIT: 4: (F2P/P2P) AIO Tab Runecrafter, using the ruencrafting tabs from the Great Orb Project (GOP) and a simple teleport method (Ring of Kinship, Ring of Dueling, Lodestone [Burthorpe or Edgeville].
Could always add support for things like Pouches and NPC Contact (To repair pouches too) but again, not sure how complicated that would make things.