here is my simple design to reach high orbit http://kerbalspaceprogram.com/forum/index.php?topic=3581.0 in this single test i was able to reach low orbit with 3coupler on, then transfer high 1M and 8M+ i guess in designated 'fly' it could reach more than 10M+ it is nice to know that method i used: burn up at Pe to reach high, and than burn up at Ap to round that, is Hohmann transfer i just use my senses