Well, out of all of Dell's acquisitions EqualLogic clearly worked out very well, Ocarina and Exanet were always about acquiring IP for cheap (Exanet was already busted so Michael Dell's ashtray change largely covered it) but Compellent seems to be rather, well, so-so, it isn't really the hit they've expected it to be among EMC upgraders but it's not CML's fault, they are simply not a replacement for top-tier EMC gear that Dell lost access to when they've severed ties last year...
OTOH Dell *is* doing some decent integration work, they just need to be more targeted and hire a lot more developers to accelerate the process because they seem to be stuck at building blocks level - they've bought CML almost 2 years ago, I've expected them to tier data between their NX-series, EqualLogic and CML by now but so far nothing in sight, even different EQL boxes weren't able to tier stuff between them a year ago IIRC...
Even basic upgrades, things that should be routine take forever at Dell: they were about ~2 *years* late on upgrading NX boxes running Windows Storage Server 2008 to version R2 - I wonder when they will move to Storage Server 2012, around 2015, maybe even later?
And anyone they acquire it will come, once again, with a *HUGE* software challenge, when they have to integrate ALL these solutions into one big, vertically compatible system... ideally you can just pick and choose which type of storage box you need and they will be able to talk to each other, even if at a limited level (for advanced mgmt I can imagine they would require CML or something similar.)
As much as I know about them I don't think Violin is too esoteric, after all Dell is trying to attack the high-end, what's better than doing it by using new tech at a very competitive price?
That being said I agree, Nimbus is probably their best bet - they have their IP that could greatly benefit from Dell's volume advantage (mfr'ing your own SSDs can get a lot cheaper when you order tens of thousands instead of hundreds per quarter, ahem), they have their own sw stack and they need money so they would be a lot easier to deal with than Violin which probably thinks they worth a lot more than Dell would pay... =)