You might want to look at this (it is rack mount - but you could use it freestanding)
http://www.xcase.co.uk/X-Case-RM413-...case-rm413.htm
or perhaps (but quite expensive)
http://www.xcase.co.uk/Chenbro-RM-21...nbro-rm215.htm
or
http://www.xcase.co.uk/Chenbro-RM-21...nbro-rm217.htm
or you could use this
http://www.xcase.co.uk/Cfi-B8253ER-5...fi-b8253er.htm
with another smaller case.
The Chenbro kit is a bit pricy - but I have bought an OEM case from them (this one http://www.xcase.co.uk/3u-short-rack...ase-rm300s.htm - has 4 internal drive bays and two external) and it is very well made. Company were good to deal with too.
Yes - that external Raid housing about would do (and it looks as if it may come with a port extender card)
I think we have rather expanded on your original requirement though!