Non working spouse qualifies for max spousal IRA Can the $ go in an existing rollover IRA from a previous qualified plan?

Yes. But by definition, the IRA would no longer be a Rollover IRA. Definition at http://www.retirementdictionary.com/Rollover-IRA.htm

Since so many things are portable these days, are there any/many disadvantages to it not being a rollover IRA?

Fortunately, PPA made the EGTRRA portability provisions permanent. Meaning, no real fear that IRA won't be rollover eligible for qualified plans in the foreseeable future.