It would be awesome to be able to select multiple line items in a proposal and then replace them all with a single SKU. Or perhaps be able to just replace all the items in a particular option with a different model.

For instance if you're doing a good/better/best sort of format, to be able to copy the good to option 1 and 2 and then go into option 2 and select "replace" on one of the speakers and have the option to replace all in option 2 with the new model instead of having it replace all of that model throughout all the options.