For stats, I much prefer stats that high level PCs can interact with. OTOH these days I'm against perma-death for deity level punching bags like Orcus & Tiamat, rather I see their defeat more as a discorporation where it will take them a century or so to reform, but they're not gone forever as long as people (or dragons) still believe in them. So Challenge 30 for Tiamat and other highest-end threats looks about right to me. If a powerful deity needs to be above 30, then better to do a multi-stage boss fight as was done for Shar in one of the 4e organised play adventures - I think my friend
@Upper_Krust did similar. Challenge 48 stats seems a bit, er, theory-w*nk, unless you have a whole
level 21-40+ PC system to support it.