Integrating Shipping Label/Manifest Printing - Recommend Pls

[buldag]

Our current Product Fulfillment system is built using Php/MySql which resides on a UNIX server.

We are looking for a script/code/software that provides us the flexibility of integrating the Shipping Label generation process to our fulfillment module.
I have tried searching but most of the Shipping manifest apps are either not compatible with UNIX or are not compatible with Php/MySQL or are not meant to be deployed online (they are standalone softwares by themselves).

The script should allow us toe fetch shipping cost data from each of the three large carriers (UPS, FEDEX and DHL)... and then once we decide what to use, it should allow us to click and print the shipping label from the app itself. The addresses data etc. will be fetched directly from the MySQL DB.

Here are some apps which I looked closely (just trying to illustrate functionality):
SONICODE-MERCURY

AIVEA ESHIP

Can somebody suggest some others? or some help toward finding a script suitable for our purposes? or maybe share your experience trying to find such a script. Any help will be appreciated.

thanks