Creating Xen-Mobile, with all the UI goodies I have in mind, would take me almost a month, considering the idea to have device specific styles.
It's way too risky to invest so much time in something that will not help me pay my bills.
To spur development, xenforo.com needs a different model than what has been done before.
If 1/200 vbulletin customers make addons ... there will be a boat load of addons.
If 1/200 xenforo customers make addons ... there will be very few addon choices.