so, FYI, Dell doesn't actually manufacture switches. They're all rebadged/oem'ed from other vendors.
So, limiting to Cisco/Juniper and you probably want the smallest enclosure possible. Actually, I don't know Juniper well enough to make a suggestion, so here is my Cisco recommendation.
Cisco 4900M switch w/ at least three 10Gbase-CX4 adapters and an 8 port 10Gbase-T module.
In ciscospeak, it's a WS-C4900M w/ a WS-X4908-10G-RJ45 and three X2-10GB-CX4.
It's a 2U semi-modular chassis with eight X2 slots along the bottom and two module-slots. The WS-X4908-10G-RJ45 is an eight port 10Gbase-T plug in module. Obviously, you could expand up to more fibre or CX4 ports using the five remaining X2 sockets at the bottom and you can also purchase a second 10Gbase-T module if you wanted more 10Gbase-T ports.
Does this work?
Edited to add the following:
If price is a concern, this is Cisco switch unlikely to be practical. It's overkill for simply a "storage switch". It can, however, do a lot of things above and beyond your average Layer2 switch. For example, hardware IPv4/IPv6 routing, ACLs, QoS policing, etc. I don't know what you want this switch for, so, well, I can't comment on that. If you get a quote on what I described above, though, I'd be amused to hear how much it costs.
I don't understand some of your comments on a previously submitted answer. At first you insist on Cisco, Dell or Juniper; but, later, you made comment a comment soliciting thoughts on a RackSwitch G8100. If you're considering other vendors and only need layer 2 switching, then I'd also suggest you check HP's ProCurve line and Force10 networks. For example, the Force10 S2410.