Hi,
my new mill has an acceleration using rated torque of the servos of 0.27g, which I find more that adequate. If you genuinely want 1g accelerations then you are looking at very serious servos.

If you use 32mm screws of 5mm pitch, then direct coupled at 3000rpm works out to 15m/min. My Deltas are rated to 3000rpm, but can (with field weakening) go to 5000rpm or 25m/min.
I detune my machine as I find these speed just too scary fast and the machine (800kg) starts lurching around the workshop....abut 12.5m/min and 0.15g are my normal settings. If I have a longer
job, or a repeat job with a well proven toolpath I'l take it up to 0.25g and 25m/min.

Let make some ballpark type calculations;

Assume 32mm diameter screws of 5mm pitch, 1m long.
Assume a servo inertia of 2 x 10-4 .kgm2 (My 750W Delta is 1.16 x 10-4.kgm2, so this assumption will be fair in the range of 750W to 1.8kW)
Axis weight of 1000kg

Jscrew=(0.032/2)2.PI. 1m. 8000 x 1/2 x(0.032/2)2 (8000kg/m3=density of steel)
=6.43 (kg) x 0.000128
=8.23 x 10-4.kg.m2

Jlinear= 1000 x 0.0052 / (2.PI)2
=6.33 x 10-4 kgm2

Thus the total inertia is:
Jtotal= (8.32 + 2 + 6.33) x 10-4 kgm2
=16.65 x 10-4 .kgm2

The inertia ratio (of inertial load vs servo inertia) is (8.32 + 6.33)/2= 7.3:1, a very achievable ratio.

Note that the momentum of the linear axis is less than the rotational momentum of the ballscrew alone, and as a consequence the rotating components, namely the ballscrew and the armature
are going to dominate (61%) the acceleration equation. This may be hard to fathom, but physics does not lie. In truth the linear mass, the axis, moves fairly slowly while the ballscrew and armature spin
really fast, and so dominate the momentum.

Just as a comparison my 750W servos have a rated torque of 2.4Nm and so with this combination:

d2w/dt2= 2.4 / 16.65 x 10-4
=1441 rad/s2

Which is equivalent to a linear acceleration of 1.147m/s2 or 0.11g.

I would suggest to you that 0.1g is a little low for your design, but a 1.5kw servo would result in a 0.2g acceleration which is very adequate for toolpath following in my experience.
If you want 1g accelerations then you'll need something like a 20Nm servo.....maybe 5kW........serious and eyewatering money.

Craig