Hi Anthony,
The 5th and 6th Dynasties are technically still the Old Kingdom.
Erm.... I know. I'm surprised you think I don't. Or puzzled really. Heheh.
However, if you are looking for evidence of a Dynasty IV Iunu as a sun cult center, I don't think you'll find much, if anything at all.
Well, my interest isn't limited to one dyansty only. The main reason for this is the evident fact, that what happened during the dynasties before affected the 4th, and similarly what we see during the dynasties after is result of the 4th. I know you don't think so (or at least you have said so, IIRC).
Yes, I have noticed there is not much evidence about Iunu in general before the 5th.
Ritva