Here is a simple LinkSubmit component that I made for our projects.
I used a Submit component with display:none and a link calling the click of the submit. That's because otherwise the Form's onsubmit event is not raised (that's needed for client side validation). Seems a bit clumsy, maybe somebody has a better idea (maybe after AJAX, JS support is coded).
I changed the render code to:
,"onclick", "document.getElementById('" + submitButton.getClientId() + "').click();return false;"
I've changed this to a bug, since this is a pretty critical feature of Tapestry 4 that has been sorely missed in Tapestry 5.
Note: I wrote my own version of the component (I didn't use the attachment). It's based on some work I did for Ping Identity recently, released with their verbal permission.