i don't know your budget concerns, or what the surplus computer stuff availability is in your area, but here is a viable option.
the APC ups system 1400va units are good for 1050 watts, they are 24volts dc front end and are very clean sine wave output and hold a dead on 60hz at 120vac in my experience. their fans are quiet and long lived, the beeper is easily shut off and they are very tough units.
i would have to look at one of mine to get a model number, but the ones i have are built to have up to 10 additional battery packs attached
so they can run virtually continuous duty at full output.
i have looked at their wave form and it is very clean on a scope, there is some distortion starting inductive loads which is to be expected.
they can surge to 1800 watts or thereabouts for 3 seconds before they trip out and have to be reset/restarted, which make starting some motor loads possible.
they are available often times for 50 bucks at electronics recycle centers, usually because of dead internal batteries which you would be bypassing to your bank anyway.
efficiency is not spectacular, the come in at ~85-87% efficient, and have a no load draw of around 50watts, which might be an issue.
having said all that, i think they have a place in any system using 24vdc battery banks, because they are readily available, tough as nails, are pure sine wave, and are relatively cheap... perhaps phantom load and somewhat lower efficiency is an acceptable compromise.
i think so.
fwiw
bob g