Best Integrated or Power Amp Under $1K?

If you can live without that preamp, I'd suggest an Adcom GFA5500 amp & GFP750 preamp.
The amp has 200wpc, and the preamp sounds very good in passive & active mode.
The amp goes for around $500.00 used, the pre around $600.00.

After owning a Stereo 70 w/ Curcio mods I doubt you would be happy with solid state. You may want to try a Manley Stingray. It should sound great with your Kestrels.

Depends on budget and your taste, but at an easy budget, the Musical Fidelity A3CR is very nice and a steal. Usually around $600.00 these days. If your taste are more toward big power and forward sounding, The Dussun V6i.
If the funds Permit, The Coda Integrateds are great.

For under $1K it will be difficult to find something equal to your Curcio 70 that won't require a refurbishing in the next 4-5 years (or sooner).

You might considering paying a tech to redo your 70. What does it need other than lytics?

You could purchase a recently rebuilt 70 (the normal looking ones go for around $600) and sell yours as an offset.

This would leave you plenty left over for better tubes, a bigger Turkey...

If you just want a change look into used Quicksilver mono block amps (many come up for under $1K/pair), but depending upon age/condition they may soon require new caps as well.