You could add up to 10 products to your basket just by typing in the product reference ('Model' field in OC), clicking view item to check the code exists and entering a quantity.
Once you'd done the above for all the items you wanted you'd click add to basket, and ALL the items in this list would get added to the basket.
i.e
On below example, on Line 1 the 'model' number text WCA091 was entered, and then view item was clicked. This found the matching product and displayed it along wih the unit price (hidden on screen shot) and quantity box where you could enter a quantity (default is '1').

Items could be removed from this shopping list by clicking the red X.
Once you'd done this for a few items you'd click the add to basket button bottom right to add all these items to the basket.
Might sound odd but it is something suitable for trade work we do, and it works well. The quick shop allows orders to be placed quicky by those who know the product codes off by heart.
I can not find anything similar on the extensions, and I don't believe it would be that difficult for someone to create this, the dynamic lookup is probably the most complicated part and adding multiple items in 1 go to the basket. I appreciate it might not be possible to do it so fluidly with OC, so it is flexible. The key need is the ability to type multiple model codes and quantities, and then adding them to the basket afterwards.
If anyone is interested please let me know what it would cost to produce.
With thanks,
Simon.