I need an inventory system for my business that can integrate with an
accounting package. Is there something out there that I can use?

I only have under $5000 to spend. I use quickbooks and the warehouse
option didn't work well.

I sell copper fixtures and tubing. It has to be multi-currency and be
able to track order from quote, to PO, to invoice. I want it to be
able to handle back orders as well. I would love it to have some
extensible platform that I could hire a programmer to tweak. For
example, my fixtures have a weight and it's great to be able to
include that on the invoice for shipping. Lastly, it would be great to
be able to alter invoices if I've made a mistake (one of the programs
I saw, multiexpress, didn't let me do this). Great plains seemed too
expensive. I want to be able to buy it and not pay monthly forever.

For 5000 Bucks, you could get 100+ companies to get your job
completed, post the job at
http://www.rentacoder.com/RentACoder/Default.asp?txtFromURL=AId_935730
:)

try www.villagemall.com.au