Transportation Management System - Drupal as an application framework

Hello,

Recently a client of ours (big corporate) asked for internet based application which will allow it's employees to order transportation to and from work premises.
After some research we came to the conclusion that Drupal will allow the best ratio in terms of cost-benefit for the given specifications.

We have built silvercab
check http://eng.silvercab.biz

(note:This is not the live system but a demo)

To build this system we used the following main modules:
cck - obvious, actually I can't recall a project we did without this module (wouldn't it make more sense to add it to the core?)
cck_field_perms - allows blocking some of the coordinator fields to the user.
cck_validation - validation rules for the time the taxi was ordered for, were inserted using CCK validation field.
jstools - contributres the jscalendar widget which is so important for the user experience.
node_order, silvercab_global - self written modules especially (not published). These modules allow tailoring of the specific actions the application is enabling for the coordinator: mass allocation of orders to trips, re-opening and cancellations of these allocations.
views - dahhh...
views_bulk_operations - allows basic support for mass actions.
workflow - each order made by an employee has a full lifecycle controlled by the workflow module.
workflow_fields - some fields permission are controlled by the order lifecycle.
actions - one of the basic requirements was to inform the employee via emails with any change at the order status. An enhancement would be using the SMS framework...

Additional modules:
auto_nodetitle
autoassignrole
autologout
date
demo
devel
fieldactions
views_bonus

Comments are very welcomed.

Udi.