Daniel,
The engineering team is working on making the WPF client more touch friendly. You may have already noticed some changes in SDK SP07/PL01 where spacing is increased in rows for drop downs, lists, etc. I believe there are also more changes planned for SP08 as well in this regard.
The only thing you could try would be in the editor under Application Settings the checkbox for Use Large Buttons. I do not know if this will affect the WPF client or not. You would just need to test it out and see.
Support is also working on a note to detail out some of the changes being made to make the WPF client more touch friendly.
--Bill