a "one page" edit form would be nice on outgoing entries as well, similar to the csv import screen where you can modify a bunch of entries before doing the import

outgoing entries, only able to delete one at a time

lots of example, but here is one:
click contacts, click vendors to show all vendors, you are only able to delete one at a time, there should be a check mark next to each one so you can mass delete, I will post other example in different comments

actually my idea here wouldn't require inventory management, many small businesses are forced to use an excel sheet or something like that because their vendors require a PO

all that is really needed to "start" this would be a list of items that have a cost attached to them so a PO could be generated and emailed to a vendor

similar to how freshbooks does it, there is no actual management of inventory but you can create items with default prices

down the road you could expand the system of course but to start simple PO emailing would suffice

my .02