You require to have three basic things in place before attempting such a project :
1. A clear project plan with definitive road-map.
2. Initial boot-finance to fund the start-up phase and operational cash to sustain through the sales cycle before you start making revenue.
3. Operations & sales team.
Once you have these in place, a 50/100 seater should take 60-90 days to go live. Sales & business development begin amost simultaneously so that you have some pilot projects to attempt when you are ready to go live.
Hope that sufices. Require more info? Write again…
Cheers, Manoj Matai