This can be done by one of cheap osrs gold either by searching the web for these items (I personally will give a brief list to those interested) or use a program designed to find the best merchandise to buy for the week. (I have seen one. It's on my laptop, since it's homemade). These products can be very hard to find, even though most of them are necessities like food as well as "skilling". Here's a list of best items to merchandize for short periods of time. Invite your friends to participate to assist you in increasing the price by buying additional of the same product.
Here's my top 10 list of merch partner who I sell my products to... I'm only giving this information away as I'm done with runningescape merchanting as I'm more focused on spending my money on developing skills. All the best! Good Luck to everyone! (Oh and I am sorry if I posted this in the wrong place and move it to the right place if you must)
I cannot really speak much about the female vocal. I'm really at a loss about what could be behind the doors, perhaps someone associated with Zaros? I just hope it's an interesting person and that there's a reason to it. Kill, fight, and stab." Update
I am praying that the boss uses the random Dungeon Generator. AS for collaboration, why not use an element where the player is disabled one player while another needs to remove them, it's the simplest way. In reality, if they use a random dungeon generator it would need to have a maximum level for each of the challenges, so that you won't have to deal with problems in dung, when half of the dungeon gets cut off due to a single door.
I think that the idea of disabling is a great idea and would tie in well with the idea that we need collaboration. It could be possible to take To'kash's deep freeze attack and focus on one person only. It could also last for an extended time period before it would melt (not infinite, though so even if you're trapped by yourself, there's a chance to escape). This would make it more difficult for players to work together.
I envision tougher buy 07 gp getting many Dung-style bosses, with nothing that you can do to win. Although some bosses are less effective than others (Lexicus is one example) I think that varying the methods required to take down bosses can make for more exciting boss battles.