Hi Daniel, Thanks for contacting us! This is an excellent suggestion, and one we will look at including in the Ribbet Text tool in a future version.
As of right now, you can achieve this through the Pro Editor tool:
1. Head to the Pro tab > Pro Editor tool > Pixlr Editor
2. Add the text and resize it as closely as possible to the size you desire
3. Select from the menu Layer > Rasterize Layer
4. Select from the menu Edit > Free Distort…
5. Move the corners to achieve the desired effect
6. Choose from the menu File > Save > OK
Let us know if we can be of any further assistance!