Thinking about build up my Eastern Dirt bike with 21+ TT. I'm tall so it may will work.
Had always small frames like 18,6.
Is there someone else riding a dirt frame? Can you post a pic?

Yeah, cliffhanger will be more difficult to get out.

i rode with my funday 20.5 for 2-3 weeks,slower style but more stable i am short though 1.69.
i ride with a 19.3 div with 13.25 and minimal offset forks sometimes so if you are 10 or more cm taller i think there will be no problem.
it must be good for rolling tricks but more dificcult for turbine by the way just slamm your back wheel if it is a dirt frame

every trick I know how to do I can do on my 20.75 S&M laf frame flatland bike.
even cliffhanger...    im 6 foot tall.

but a dirt frame may have 13.75 CS which i dont think is good for anything flatland related...

from what I can find the laf was 13 3/4, now that may not be slammed. So I'd say minimum would be 13.5 at the very smallest, but probably 13.65 slammed.

CS length is preferance and that mainly goes by what tricks you do. CJ had a laf and rocked it. sorry ranting