Ordering, orders editing, different shipping for different countries

Hey all, go couple of newbie problems that give me headache :lamo:

My shop has over 3000 items and average order has around 25 items. Thats why I need to

• edit placed orders in case one of the items is not available or they order more items than available items.

• in the products listing change the number of items to order to a pulldown menu that would disallow them to order more than I have.

• mass editing (not automated) of prices. Because now every time I need to edit price, I have to go to edit dialog and change price there. If I need to do this for 100 items, its a real pain especially when prices change quite often (collectibles)

• see category in packaging slip, because there are items with same name in different categories. Now I have to go to the database trough MyPhpAdmin and check the ID of every item ordered.

Thanks for sugestions and tips!

• edit placed orders in case one of the items is not available or they order more items than available items.
  You should be able to get this function by using the quantity in stock for each catalog item. and enable the 'not allow ' in the admin > stock
• mass editing (not automated) of prices. Because now every time I need to edit price, I have to go to edit dialog and change price there. If I need to do this for 100 items, its a real pain especially when prices change quite often (collectibles)
  You might find the ezpopulate module beneficial for this.
• see category in packaging slip, because there are items with same name in different categories. Now I have to go to the database trough MyPhpAdmin and check the ID of every item ordered.
  You can use the model # in the product entry area to differentiate these items.