A while ago I first heard about the Thummer, an expressive midi controller which is using the wonderfull Wicki button layout. Sadly the development of the Thummer didn’t make it, but my interest in isomorphic button layouts was born.
One lucky extra feature of the Wicki layout is that is fits very good on a normal computer keyboard. There are a number of ways to use this, most notably the synthesizer 2032, which runs well under Linux through Wine. Another option is vkeybd using a wicki keymap (save in your homedir as .vkeybdmap) using another synthesizer.
There are various flash apps online where you can try this. However, flash has a very limited sound support. Since Flash 10 this has been improved, but after a promising beta the final version has very bad latency.
Have fun playing and don’t hesitate to send a message!