that case will do SLI fine, might be a bit tight with the really top end cards, but it'll be fine, if the case can accept a stand size ATX mobo, it'll work, currently no cards are longer than the ATX format boards... might have to place hard drives above & below in the bays behind the card, but not a big deal.
The Antec 900 would be a bit better with more room to manuever in the case upgrading & what not, but even that 300, SLI should be ok, just that it will be a tight fit with power plugs & if any ports on mobo behind card slots.
as to the PSU, it should fit also. on the same note as the PSU, you don't need a whopping 800W PSU for SLI, the 600 & 620's previously posted should do fine, just make sure their quality PSU's (both are), & and enough Amperage on the +12V rails...
of which both should have.
if you were maybe running Quad SLI with 2x 9800GX2's or maybe 2 GTX280's, then it might be iffy, but even then I suspect it would be fine?