The best Keyboard Phones comes from HTC,
your Device is like the HTC Touch pro II und the HTC 7pro. Have a 5 rows keyboard with Numbers and Letters in one Layout and the Display that cline up after slide out the Keyboard is a Dream.
I try some Nokias like the N97 and a Dells Venue pro, but they have never a Change against the Keyboard Functionality of an HTC Device.
I have devices from the first Windows Mobiles (5.0 to 6.8) like the Qtek9100 (HTC) then a HTC TyTN II, a HTC Diamond touch Pro and at last the HTC touch pro II.
After that Experience the Windows Phone follows with my all time favorite the "HTC 7 Pro"!
I very happy to see your Produkt and hope for an successful start. When you bring one with a German QWERTZ keyboard i will let back the Windows and use an Android Device from FXtec