Pretty much what I was thinking as well, Whitey impregnates Masaki or leaves some trace of his essence, then we get Ichigo eventually bearing a striking appearance to him (or if you still think shinigami can impregnate living people, that could explain the similarities of zanpakutos between isshin and ichigo, assuming they're somewhat hereditary). And it would make sense as Metastacia (the hollow that killed Kaien) was another of Aizen's creation, thus further lending truth to Aizen's statements about his role in Ichigo's creation if he used Kaien's soul after he was killed to create Whitey, and so on.This page caught my attention: http://www.mangapanda.com/bleach/532/6
Based on what Kaname said, could this Hollow have been created using the soul of Kaien? People have commented that Kaien and Ichigo look alike and there's no denying this "White" Hollow looks like out of bonkers Hollow 2 Ichigo.
But yeah, the only hitch is, when did Kaien die exactly? The timeline is off potentially as it's not very specific as to when that happened really, we just know it's more recent than long ago like during the vizored arc. So it's more than possible...guess we'll see though after a couple of filler chapters.