Well from what I've seen (disclosure: bought an Oly e330 myself, but haven't housed it yet) Olympus isn't charging much more for their dSLRs than for a high-end point and shoot (MSRP might be higher, but they can't be ignorant of the real 'street price' their cameras end up going for), and that includes with a pretty darn good kit lens. But your point is quite valid about the cost of the overall rig going up by an order of magnitude almost. Oly does offer their own dSLR housings as well which cuts costs, and let's face it, you COULD go with a smaller strobe option (in the e410 and Oly housing instance, even stick to using the internal strobe, with the same limitations of using an internal strobe on quite similarly priced high-end housed PnS) and reduce some of that cost considerably. I think the added cost of the dSLR rig is often because you want to take advantage of the extra flexibility to really do justice to it...different lenses, thus different lens ports, external strobes plus arms, etc.
Even the new e3 "pro" dSLR from Oly is debuting at what...$1200 or so? vs. $3-4k for the top of the lines from others? Not that I'm trying to say they're equivalent; not trying to get into that sort of anatomical measurement discussion.
I kind of agree with ce4 that it seem like Oly is sort of leading customers to their dSLRs, but also intentionally keeping their dSLRs a little more reachable by the average con- or pro-sumer so to speak, rather than truly competing at the absolute top of the category. It's kind of hard to say they've 'forsaken' the UW community when they seem to offer the most manufacturer-branded dSLR housings, their own rebadged UW strobe, UW strobe housings for their topside strobes, etc. Canon probably has more UW housings overall but Canon also sells more different PnS 'lines'.
As for the extra bulk and task loading, strangely enough I noticed when I added my Ike DS50 which necessitated a tray and arm to my A520, I think I got *better* at camera handling. Costs me some air consumption and thus bottom time (I'm a bit of a walrus) but the higher "inertia" of the rig I think stabilized my handling and the higher two-hand load forced me to be more conscious of using legs only for positioning, instead of sometimes flailing with a 'free' hand when just using the A520 housing alone. Plus having a nice beefy grip (the strobe arm mount attached to the base) vs. just 'holding' a housing. It just seems more natural, strangely enough.
I'm really looking forward to housing my e330 and upgrading to a still larger strobe...but that darned daughter in college thing is getting in the way of my conspicuous electronics consumption budget!
