This is something that WebERP has, which I find useful... it should be possible to give customers and suppliers short, mnemonic names which can be used for lookup. Three examples from my WebERP installation:
TCAMP - Training Camp
SPRNG - Spring Technology
JPLTD - James Palmer Ltd
It is much easier to remember customers and suppliers by a 5-letter mnemonic than by a sequentially-assigned number.
Creating a PO or an Invoice (or other transaction) could then be effected by entering either the customer/supplier number or the shortname.