Joel,
Like Mark I am not an engineer but I remember being told that if the bottom chord is kept within the bottom third of the truss it is considered the same structurally as if it is at the truss base. Going on this assumption and based on a 22' inside total span with 12:12 pitch you could move the bottom chord up a max of 3'8". With a 10' sidewall height this would give you a nominal center height of 13'8". The width at this point would be a nominal 14'7". A King Post truss design or rafter/collar tie application would be practical. Please verify the 1/3 rule with a qualified engineer before taking my word as gospel. I could be very wrong.
