heres a pic of my old seatpost bars. i bought a 7/8 pipe for them. the best thing to do is buy the seat post. go in the sr store when its open and buy a buff bar replacement crossbar and put it through your seat post.
uh... you would need a seat post that is really really long.. and make like that internal bar thing that pete was talking about. i think you should just buy buffs or make 1 peice bars.
you put the seat post where your ttube goes, and get a pipe and put it through the seat post.
if your asking about the ttube, you buy a pipe and put it through the ttube where your normal bars go. get 3/4 od pipe and stick it through the ttube and bolt it.
depends some seat posts are really small cuz i guess its lighter for the bikers u just have to be smart and buy one that would add up to 22 inch with ur head tube