Well... I had a go at using the EAGLE v7 hierarchical design feature.
As matters currently stand, it falls considerably short of being useful.
Yes, it's a handy way of organizing the schematic, and handling replicated structures (I need to deal with eight copies of one module, each of which has four copies of a sub-module).
It doesn't help the least friggin' bit with replicated layout. I'm thinking it actually makes the layout process even more awkward.
The resulting reference designators are appalling (QUAD2:CELL1:R34, for example). They can't be re-sequenced into geographical order, but I guess that's OK, because there's no way they could be included on the silkscreen, and putting them on an assembly drawing would require some serious miniaturization.
Trying to debug a board...? This could get very annoying, very fast.
Then there's the question of whether the assembly house will accept that refdes format. And whether the BOM and pick-and-place export utilities I've been using will deal with it... or indeed with a hierarchical design.
Also, there doesn't appear to be any way of selecting a hierarchy object per se, so that its components can be moved apart from the mass and onto a layout template. Highlighting in the schematic and alt-tabbing (the switch view button would remove the highlight!) to the layout gets a somewhat useful indication of what's what, but the moment you select the move tool, the highlight goes bye-bye.
So, nope. Not useful for what I'm trying to accomplish. Back to the old flat schematic, with eight copies of probably a B-size sheet with a complete four-cell cluster plus the common stuff. That'll be enough of a headache, but at least the reference designators will be a sane length.
This also means that the next phase of the project will be more laborious than I'd hoped, but, hey, it's hourly.
(Maybe I'll rummage around the 'net a bit later, and see if there are any useful tips for actually using the hierarchical features. Should I find anything to change my mind, I'll post an update here.)