Creating an advanced webapp: "work-log" with grails

I have played with the idea of creating my own time-tracker app, and after some prototyping I think I have some useful ideas. So I will hopefully have a series of blog posts where I describe the different 

First of all: my #1 tool is grails. I´m a java-dude, but after playing around with grails for a while I know that java cannot compete with the productivity of grails. 

Second: for authentication I need to use google(it would be nice to integrate with their marketplace for google-apps if this goes anywhere). The users have to be divided into 1) uber-users(me, or the application-maintainer), 2) super-users for a company(CEO) 3) department-managers 4) normal users

Third: I´m no design guru, so I need some good css styling for free. I´m thinking maybe twitter-bootstrap can help me out, but i´m not sure yet. 

Fourth: my domain-model will fit the needs of a multi-department organisations with local managers and company-wide managers. 

Fifth: I need to export data as csv and pdf to create some invoices. Maybe with customized logos. Don´t know how I will do this yet, but I have some experience with itext and "flying saucer".

I will post all my progress on github, and have (hopefully) frequent deployments to cloudfoundry. 

more to come....