*Yawn* yea can't sleep.
But...! Kisuke seperated Ichigos soul from his body, eventually cutting his chain of fate, seperating his body from his soul. Thus throwing him into the death cycle.
Ichigo is a rare case, I doubt any soulreaper other than him has an inner hollow. Due to the fact that they most likely passed over before the hollow process began. Or they were born there.
Ok so, once you die, your a spirit until you:
A: Become a hollow
B: Become a soul reaper
C: Your spirit is just sent to Soul society to live, (becomeing a soul reaper there)
Soo...Ichigo being forced into one of those 3 we can cross out option C since, noone was going to pass him over. He started his hollow transformation, and in the mist of it, found his shinigami abilities, which suppresed his hollow transformation. But didn't get rid of the hollow, just forced him into his soul. Thus creating a shinigami with an inner hollow.