Accpac International www.accpac.com
has some good products. They sell via authorized re-sellers. A list of re-sellers is available on their site.
Their products started out as a Windows only, but now support Linux. The product will work using IBM's DB2 or Pervasive Software's Pervasive.SQL as the database backend. Pervasive's site is www.pervasive.com
I have installed it in the following environment:
Linux server running Samba.
Windows based clients.
Pervasive.SQL loaded on the Linux server.
Here is a link to one of their Linux success stories http://www.accpac.com/products/epos/
BTW make sure that you clearly and completely define your accounting requirements before you choose a software. Too many companies buy the software then find out that it cannot do something that is essential to their business.