After some days I managed to have some time to keep hacking on the grid. Before this I had some issues about the renderers and still I can't make the Combo and Spin Button editors work without problems.
At least today I added a cool feature: you can now have columns with different width. Right now the width for every column is computed when the model is set. It is the maximum with of all of its cells.
Now, I just need to put the header and sidebar and I'll be happy for one more week. So if I can do it tomorrow, we will have 0.0.2 very soon.