Just a bit of a twist on the above themes. Consider an unpowered mixer with powered speakers instead of a powered mixer and "hollow" speaker cabinets. Gets just the right amount of power where you need it.
My little bitty Mackie 1202 VLZ with 4 mike preamp channels and a pair of (heavy) JBL Eon powered 15s and the obligatory Shure 57/58 fills a lot of space for the Misses and my duos. Downside - need a powered monitor. I'm using a Fender Ampcan (battery powered) for both a stage monitor and a go anywhere cordless.
Just added a Mackie 1402 unpowered mixer and do the whole ceili band with 10 mike chanels.
Has anybody else gone the powered speaker route?