You can see the final project here: http://crabandfish.blogspot.com/2012/10/lil-archers-bed-its-done-its-do…
It was time for our son to move to a big-boy bed! We looked at tons of plans, but none were quite what I wanted. In the end, fish modified plans for Ana White's Camp Loft Bed with Stair. We wanted to make it a bit shorter because we only have 8' ceilings and there is a ceiling fan in the room. We spent about $80 for the lumber and invested in a kreg jig as well. The bed is stained with Minwax Golden Oak. We bought a 10" deep twin-sized foam mattress for the bed - if you are adding a coil mattress and boxspring, the bedside rails would definitely need to be higher.
Our son LOVES it! He is almost three and is easily able to navigate the stairs, which I don't believe will become too "baby-ish" as he grows older. If they do, the steps can easily be removed from the frame without losing structural integrity.
The underbed area has a great "cool" factor - we hang blankets to create forts, and it has become a place our son gravitates to for reading, playing, anything!