Hi Jim
We use a Yamaha Stage-Pas 500 at SWSC, this is an all in one solution that may worth auditioning given your requirements. The quality of sound is excellent, we use it for backing tracks, live band vocals and keyboards.
The kit comprises of two speakers with a small mixer/amp that resides in the back of one of the speakers for transport, there is a separately available suitcase sized case for transportation. If this proves to be too heavy it is possible to pack and remove a speaker at time to take them in and out of venues or loading at home.
A few meetings ago one of our members put an iPad with amp emulation app through it and it was pretty impressive (VOX AC30), if we had one of our AC 30's go down this would certainly be a viable backup.
They also do a 300 watt version for small venues, one of the reviewers states on this thread that it cuts out at all his parties for an hour. We did get that at one of our Christmas functions, but this was once in over a two year period, it was very loud indeed and re-set under ten minutes. The protection cuts in when it exceeds limits that are likely to cause damage.
http://usa.yamaha.com/products/live_sou ... gepas_500/Hope this helps
Regards
Gary